Optical nondestructive testing device for gear tooth surface cracks

Abstract

The invention discloses a gear tooth surface crack optical nondestructive testing device, and relates to the technical field of nondestructive testing, the gear tooth surface crack optical nondestructive testing device comprises a support frame, a confocal multi-mode optical assembly and a piezoelectric feedback loading assembly, the confocal multi-mode optical assembly and the piezoelectric feedback loading assembly are arranged on the top of the support frame, the confocal multi-mode optical assembly comprises an annular LED lamp, a terahertz emitter, a terahertz receiver, a laser emitter, a pinhole diaphragm and a photomultiplier, the annular LED lamp is used for emitting exciting light to enable the fluorescent agent at the crack to emit light, and the photomultiplier is used for receiving and amplifying a fluorescence signal; through the synergistic effect of the confocal multi-mode optical assembly and the piezoelectric feedback loading assembly, full-dimension and high-precision nondestructive detection of gear tooth surface cracks from subsurface initiation defects to working condition closed cracks is achieved, and the device is different from a traditional passive detection scheme depending on a single optical mode, static parameterization analysis and empirical interpretation. And the crack detection is earlier, more accurate, more adaptive and more reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-destructive testing, in particular to a gear tooth surface crack optical non-destructive testing device. BACKGROUND

[0002] The gear tooth surface crack optical non-destructive testing device is a device for high-precision detection of gear tooth surface cracks through a non-contact manner based on optical principles. Its core advantage is that it can quickly and accurately identify micro defects on the tooth surface without damaging the measured object, and it is widely used in fields such as automobile manufacturing, wind power equipment, aerospace, etc. that have extremely high reliability requirements for gears.

[0003] In the current gear tooth surface crack optical non-destructive testing device, passive detection mode is prevalent, relying on offline sampling inspection, single-mode exploration, and static parameter analysis. Operators often adjust optical parameters based on experience, and use simple image segmentation to identify micro cracks. This mode has core bottlenecks such as detection depth blind area and lack of dynamic defect response, making it difficult to meet the needs of modern gear manufacturing for full number, online, and quantitative diagnosis. However, this contradiction is dramatically amplified in the detection of fatigue cracks that are closed under sub-surface cracks and working loads. At the optical detection end, traditional single-point sensors cannot adapt to the dynamic opening displacement of cracks and the differences in multi-spectral response. Static imaging structures cannot match the curvature of the tooth surface and the fluctuations in material reflection characteristics. Centralized light paths are also prone to installation overlap and light path crosstalk in multi-modal modules, forming non-orthogonal imaging blind areas, signal attenuation channels, and stray light interference paths. At the loading and detection coordination level, static loading structures cannot accurately regulate dynamic forces to stabilize the opening and closing of cracks, and the separation control mode leads to delayed coordinated response, thereby exacerbating the risk of missed detection. The lack of signal-to-noise ratio causes missed detection of closed and sub-surface defects that are not captured, and the data distortion caused by stray light signals not only leads to a lack of early warning and misjudgment of service life, but also may damage the tooth surface due to improper loading, ultimately leading to the risk of unplanned downtime of the gear system, assembly replacement, and non-linear increase in detection costs, which cannot meet the full-dimensional and high-precision requirements of industrial batch detection.

[0004] Therefore, we propose a gear tooth surface crack optical non-destructive testing device to solve the problems mentioned above. SUMMARY

[0005] The purpose of the present application is to provide a gear tooth surface crack optical non-destructive testing device that, through the coordinated action of a confocal multi-modal optical assembly and a piezoelectric feedback loading assembly, achieves full-dimensional and high-precision non-destructive detection of gear tooth surface cracks from sub-surface defects to working condition closed cracks. This is different from traditional passive detection schemes that rely on a single optical mode, static parameterization analysis, and experiential interpretation, making crack detection earlier, more accurate, more adaptive, and more reliable.

[0006] In order to achieve the above object, the present application provides the following technical scheme: a gear tooth surface crack optical nondestructive testing device, a support frame, a confocal multi-modal optical assembly, a piezoelectric feedback loading assembly, the confocal multi-modal optical assembly and the piezoelectric feedback loading assembly are arranged on the top of the support frame, and the piezoelectric feedback loading assembly is arranged on the top of the confocal multi-modal optical assembly; The confocal multi-modal optical assembly comprises a ring-shaped LED lamp, a terahertz transmitter, a terahertz receiver, a laser transmitter, a pinhole diaphragm and a photomultiplier tube, the ring-shaped LED lamp is used for emitting excitation light to make the crack fluorescent agent emit light, the photomultiplier tube is used for receiving and amplifying the fluorescent signal, the terahertz transmitter and the terahertz receiver are used for sub-surface crack detection, and the pinhole diaphragm is used for filtering non-focal stray light. The piezoelectric feedback loading assembly comprises a ring-shaped pressure sensor, a middle layer piezoelectric ring, three micro-displacement sensors and a micro-pressure sensor, the ring-shaped pressure sensor is used for real-time monitoring of the total loading force acting on the tooth surface, the middle layer piezoelectric ring is used for providing micron-level displacement output based on the piezoelectric effect, the three micro-displacement sensors are uniformly distributed along the circumference, the three micro-displacement sensors are used for capturing the instantaneous displacement mutation of the crack opening, and the micro-pressure sensor is used for monitoring the local contact force of the tooth surface.

[0007] Preferably, a fixed base is fixedly welded on the top of the support frame, a motor dividing disc is installed on the top of the fixed base, a three-jaw chuck is rotatably connected to the rotating end of the motor dividing disc, a gear is clamped and fixed on the top of the three-jaw chuck, an eddy current sensor is arranged on the top of the fixed base, and the eddy current sensor is used for material identification of the gear, and a gantry is boltedly connected to the top of the fixed base.

[0008] Preferably, the confocal multi-modal optical assembly further comprises a linear motor sliding table, a first sliding block is slidably connected to the outer surface of the linear motor sliding table, a connecting plate is fixedly welded to the bottom of the first sliding block, a Z-axis linear module is boltedly connected to one side of the outer wall of the connecting plate, and the Z-axis linear module is used for providing vertical motion, a second sliding block is slidably connected to the outer surface of the Z-axis linear module, an extension plate is fixedly welded to one side of the outer wall of the second sliding block, a flange plate is fixedly connected to the bottom of the extension plate, and the inner surfaces of the flange plate are insertedly connected with the outer surface of the photomultiplier tube.

[0009] Preferably, the bottom of the flange plate is connected with an optical seat, and the optical seat is used for forcing the three optical paths of laser, terahertz and fluorescence to be coaxial, an annular fixing ring is fixedly connected between the inner surfaces of the optical seat, the bottom of the annular fixing ring is connected with the top of the annular LED lamp, the inner surfaces of the optical seat are symmetrically connected with sliding rails, the inner walls of the two sliding rails are connected with sliding plates, the two sliding plates are connected into one body through a cross frame, the top of the two sliding plates is connected with four optical filters, the four optical filters are of four different wavelengths, one side of the outer wall of one of the sliding plates is fixedly connected with a gear rack, and the outer wall of the second sliding block is boltedly connected with a mounting seat.

[0010] Preferably, the top of the mounting seat is fixedly provided with a micro motor, the shaft end of the micro motor is rotatably connected with a transmission spur gear, the outer wall of the transmission spur gear is meshedly connected with the outer wall of the gear rack, the outer surfaces of the optical seat are connected with the outer surfaces of a terahertz emitter and a terahertz receiver respectively, the inner surface of the optical seat is connected with a first collimating mirror through an adjustable support, and the first collimating mirror is of a parabolic shape.

[0011] Preferably, the first collimating mirror is used for changing the divergent wave emitted by the terahertz emitter into a parallel straight wave, the emitting end of the terahertz emitter is opposite to the first collimating mirror, the inner surface of the optical seat is boltedly connected with a first focusing objective lens, and the first focusing objective lens is designed to be inclined downward by forty-five degrees, the receiving end of the terahertz receiver is opposite to the first focusing objective lens, and the first focusing objective lens is used for converging the terahertz waves reflected from the internal cracks of the gear, a ring-shaped groove is formed in the wall thickness of the optical seat, the inner surface of the ring-shaped groove is connected with the outer surface of a laser emitter, and the inner surface of the optical seat is connected with a first turning mirror and a second turning mirror, and the laser emitting end of the laser emitter is opposite to the first turning mirror.

[0012] Preferably, the first turning mirror and the second turning mirror are both designed to be inclined downward by forty-five degrees, the inner surfaces of the optical seat are threadedly connected with a second collimating mirror and a second focusing objective lens respectively, and the second collimating mirror is arranged on the top of the second focusing objective lens, the second collimating mirror is used for arranging the laser beam into parallel light, and the second focusing objective lens is used for focusing the multiple parallel light into a micro light spot, the outer surface of the optical seat is provided with a mounting hole, the inner surfaces of the mounting hole are insertedly connected with the outer surfaces of a pinhole diaphragm, and the outer surface of the optical seat is boltedly connected with a photoelectric detector, and the laser receiving end of the photoelectric detector is opposite to the pinhole diaphragm.

[0013] Preferably, the piezoelectric feedback loading assembly further comprises an outer fixing sleeve, the top of the outer fixing sleeve is threadedly connected with the bottom of the optical seat, the inner surface of the outer fixing sleeve is connected with the outer surface of the annular pressure sensor, a plurality of elastic clamping springs are connected between the inner surface of the outer fixing sleeve, and the plurality of elastic clamping springs are uniformly distributed along the circumference of the inner surface of the outer fixing sleeve.

[0014] Preferably, the inner surface of the plurality of elastic clamping springs is connected with the middle layer piezoelectric ring, the inner surface of the middle layer piezoelectric ring is fixedly connected with one side of the outer wall of the three micro displacement sensors, and the three micro displacement sensors are arranged along the height of the middle layer piezoelectric ring.

[0015] Preferably, the bottom of the middle layer piezoelectric ring is provided with four grooves, a threaded adapter seat is connected between the inner surface of the four grooves, the bottom of the threaded adapter seat is threadedly connected with a flexible loading head, the bottom of the flexible loading head is embeddedly connected with the top of the micro pressure sensor, and the bottom of the flexible loading head is connected with a flexible contact pad.

[0016] Compared with the prior art, the present application has the following advantages: In the present application, through the synergistic effect of the confocal multi-modal optical assembly and the piezoelectric feedback loading assembly, full-dimensional and high-precision non-destructive testing of gear tooth surface crack from subsurface initiation defect to working condition closed crack is realized, which is different from the passive detection scheme of traditional single optical mode, static parameterized analysis and empirical interpretation, so that the crack detection is earlier, more accurate, more adaptive, and more reliable. The confocal multi-modal optical assembly physically constrains the three light paths of fluorescence, terahertz and laser on the same axis through the mechanical forced confocal structure of the stepped sleeve, completely solves the problems of signal attenuation, data non-co-location and stray light interference caused by focal point deviation and light path crosstalk of traditional multi-module discrete optical system, and finally the intelligent opening of the piezoelectric feedback loading assembly and the accurate synchronous detection of the opening area by the confocal multi-modal optical assembly form a trigger linkage in time and a focal point coincidence in space, which together constitute a closed-loop precision diagnosis of the mechanical excitation and optical response of the tooth surface crack, and completely break through the inherent contradiction between detection depth, defect adaptability and detection accuracy in the traditional detection scheme. Secondly, the piezoelectric feedback loading assembly realizes the precise dynamic force control of the tooth surface from macro Newton level pre-tightening to micron level crack opening displacement through the three-layer nested structure and closed-loop control logic of the annular pressure sensor, the middle layer piezoelectric ring and the micro displacement sensor, and forms an adaptive triggering mechanism for the perception and response of closed cracks by sensing the instantaneous displacement mutation of crack initiation and opening and immediately suspending the loading force, which fundamentally eliminates the force control mismatch technical bottleneck of the traditional static loading scheme in the closed crack area. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a front view structure perspective view of the gear tooth surface crack optical nondestructive testing device of the application; Figure 2 It is a side view structure perspective view of the gear tooth surface crack optical nondestructive testing device of the application; Figure 3 It is an installation position structure schematic diagram of the confocal multi-modal optical assembly and the piezoelectric feedback loading assembly in the gear tooth surface crack optical nondestructive testing device of the application; Figure 4 It is an installation position structure schematic diagram of the confocal multi-modal optical assembly in the gear tooth surface crack optical nondestructive testing device of the application; Figure 5 It is an installation position structure schematic diagram of the sliding plate, the optical filter and the gear rack in the gear tooth surface crack optical nondestructive testing device of the application; Figure 6 It is an installation position structure schematic diagram of the Z-axis linear module and the second sliding block in the gear tooth surface crack optical nondestructive testing device of the application; Figure 7 It is an installation position structure schematic diagram of the flange plate, the optical seat and the photomultiplier tube in the gear tooth surface crack optical nondestructive testing device of the application; Figure 8 It is an installation position structure schematic diagram of the second focusing objective lens and the second turning mirror in the gear tooth surface crack optical nondestructive testing device of the application; Figure 9 It is a structure enlarged view of A in Figure 5 ; Figure 10 It is a structure enlarged view of B in Figure 5 ; Figure 11 It is a structure enlarged view of C in Figure 7 ; Figure 12 It is a structure enlarged view of D in Figure 7 ; Figure 13 It is an installation position structure schematic diagram of the piezoelectric feedback loading assembly in the gear tooth surface crack optical nondestructive testing device of the application; Figure 14 It is an installation position structure schematic diagram of the outer fixed sleeve and the annular pressure sensor in the gear tooth surface crack optical nondestructive testing device of the application; Figure 15 It is an installation position structure schematic diagram of the middle piezoelectric ring, the threaded adapter seat and the flexible contact pad in the gear tooth surface crack optical nondestructive testing device of the application; Figure 16 It is a structure enlarged view of E in Figure 15 ; Figure 17 is an enlarged view of the structure at F in Figure 15 is an enlarged view of the structure at F in Figure 18 is an enlarged view of the structure at G in Figure 15 is an enlarged view of the structure at G in

[0018] In the figure: 100, support frame; 200, fixed base; 300, motor index plate; 400, three-jaw chuck; 500, gear; 600, eddy current sensor; 700, gantry; 800, confocal multi-modal optical assembly; 801, linear motor sliding table; 802, first sliding block; 803, connecting plate; 804, Z-axis linear module; 805, second sliding block; 806, extension plate; 807, flange plate; 808, optical seat; 809, annular fixing ring; 810, annular LED lamp; 811, sliding rail; 812, sliding plate; 813, optical filter; 814, rack; 815, mounting seat; 816, micro motor; 817, transmission spur gear; 818, terahertz emitter; 819, first collimating mirror; 820, first focusing objective lens; 821, terahertz receiver; 822, laser emitter; 823, first steering mirror; 824, second collimating mirror; 825, second focusing objective lens; 826, second steering mirror; 827, pinhole diaphragm; 828, photodetector; 829, photomultiplier; 900, piezoelectric feedback loading assembly; 901, outer fixed sleeve; 902, annular pressure sensor; 903, elastic clamp spring; 904, middle piezoelectric ring; 905, grooving; 906, micro displacement sensor; 907, threaded adapter; 908, flexible loading head; 909, micro pressure sensor; 910, flexible contact pad. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] As shown in Figures 1-2 , the present embodiment discloses a gear tooth surface crack optical nondestructive testing device, a support frame 100, a confocal multi-modal optical assembly 800, and a piezoelectric feedback loading assembly 900. The confocal multi-modal optical assembly 800 and the piezoelectric feedback loading assembly 900 are both arranged on the top of the support frame 100, and the piezoelectric feedback loading assembly 900 is arranged on the top of the confocal multi-modal optical assembly 800. As shown in Figure 8 , and Figures 11-12As shown, the confocal multi-modal optical assembly 800 includes a ring-shaped LED lamp 810, a terahertz transmitter 818, a terahertz receiver 821, a laser transmitter 822, a pinhole diaphragm 827, and a photomultiplier tube 829, the ring-shaped LED lamp 810 is used to emit excitation light to make the fluorescent agent at the crack emit light, the photomultiplier tube 829 is used to receive the fluorescent signal and amplify, the terahertz transmitter 818 and the terahertz receiver 821 are used for subsurface crack detection, and the pinhole diaphragm 827 is used to filter non-focal stray light. As shown, the piezoelectric feedback loading assembly 900 includes a ring-shaped pressure sensor 902, a middle layer piezoelectric ring 904, three micro displacement sensors 906, and a micro pressure sensor 909, the ring-shaped pressure sensor 902 is used to monitor the total loading force acting on the tooth surface in real time, the middle layer piezoelectric ring 904 is used to provide micron-level displacement output based on the piezoelectric effect, the three micro displacement sensors 906 are uniformly distributed along the circumference, the three micro displacement sensors 906 are used to capture the instantaneous displacement mutation of the crack opening, and the micro pressure sensor 909 is used to monitor the local contact force of the tooth surface. Figures 16-18

[0021] This embodiment mainly aims at the fact that in the current gear 500 tooth surface crack optical nondestructive detection device, the passive detection mode is generally used, which relies on offline sampling inspection, single-mode exploration and static parameter analysis. The operator often adjusts the optical parameters according to experience, and simply divides the image to identify the micro crack. This mode has the core bottlenecks of detection depth blind area and lack of dynamic defect response, which is difficult to match the demand of modern gear 500 manufacturing for full number, online and quantitative diagnosis. However, this contradiction is sharply amplified in the detection of fatigue cracks closed under subsurface emerging cracks and working load. On the optical detection end, the traditional single-point sensor cannot adapt to the difference between the dynamic opening displacement of the crack and the multi-spectral response, and the static imaging structure is difficult to match the curvature of the tooth surface and the fluctuation of the material reflection characteristics. The centralized light path is also easy to cause the installation overlap of multi-modal modules and the light path crosstalk, forming the non-orthogonal imaging blind area, signal attenuation channel and stray light interference path. On the loading and detection cooperation level, the static loading structure cannot accurately regulate the dynamic force to stabilize the opening and closing of the crack, and the separate control mode leads to the delay of cooperative response, thereby aggravating the risk of missed detection. The closed and subsurface defects that are not captured are missed due to insufficient signal-to-noise ratio, and the stray light signal causes data distortion, which not only causes the lack of early warning and the misjudgment of service life, but also may damage the tooth surface due to improper loading, finally leading to the risk of unplanned shutdown of the gear 500 system, assembly replacement and nonlinear increase of detection cost, which cannot meet the full-dimensional and high-precision requirements of industrial batch detection.

[0022] ​The embodiment is completed to solve the problems of the prior art. Through the cooperation of the confocal multi-modal optical assembly 800 and the piezoelectric feedback loading assembly 900, the full-dimension and high-precision nondestructive testing of the gear 500 tooth surface crack from the subsurface initiation defect to the working condition closed crack is realized, which is different from the traditional passive detection scheme relying on single optical mode, static parameterized analysis and empirical interpretation, so that the crack detection is earlier, more accurate, more adaptive and more reliable. The confocal multi-modal optical assembly 800 physically constrains the fluorescence, terahertz and laser three light paths on the same axis through the mechanical forced confocal structure of the stepped sleeve, completely solves the signal attenuation, data non-co-location and stray light interference problems caused by focal point offset and light path crosstalk of the traditional multi-module discrete optical system, and finally the piezoelectric feedback loading assembly 900 intelligently opens the crack, and the confocal multi-modal optical assembly 800 accurately synchronously detects the opening area, forms a trigger linkage in time and realizes focal point coincidence in space, and together constitutes a closed-loop precision diagnosis of the mechanical excitation and optical response of the tooth surface crack. It completely breaks through the inherent contradiction between the detection depth, defect adaptability and detection accuracy of the traditional detection scheme. Secondly, the piezoelectric feedback loading assembly 900 realizes the accurate dynamic force control of the tooth surface from the macro Newton level pre-tightening to the micron level crack opening displacement through the three-layer nested structure and closed-loop control logic of the annular pressure sensor 902, the middle piezoelectric ring 904 and the micro displacement sensor 906. Through the sensing of the instantaneous displacement mutation of the crack initiation and opening and the immediate hovering of the loading force, an adaptive triggering mechanism for sensing and responding to the closed crack is formed, which fundamentally eliminates the force control mismatching technical bottleneck of the traditional static loading scheme in the closed crack area.

[0023] According to Figures 1-3 As shown in the figure, the top of the support frame 100 is fixedly welded with a fixed base 200, the top of the fixed base 200 is provided with a motor dividing disc 300, the rotating end of the motor dividing disc 300 is rotationally connected with a three-jaw chuck 400, the top of the three-jaw chuck 400 is clamped and fixed with a gear 500, the top of the fixed base 200 is provided with an eddy current sensor 600, and the eddy current sensor 600 is used for material identification of the gear 500, and the top of the fixed base 200 is boltedly connected with a gantry 700.

[0024] In the embodiment of the present application, first, the support frame 100 adopts Q235 steel structure, fixed with the workshop floor through the bottom reserved expansion bolt hole, which can provide a stable bearing foundation for the whole device, and can reliably bear the overall weight of the confocal multi-modal optical assembly 800 and the piezoelectric feedback loading assembly 900, effectively avoiding displacement deviation due to vibration during equipment operation, wherein the fixed base 200 is made of 304 stainless steel material, fixed with the support frame 100 by welding, and the motor indexing disc 300 installed on the top thereof adopts servo drive design, which can drive the three-jaw chuck 400 to rotate accurately, realize full-circle non-dead-angle detection of the gear 500, secondly, the three-jaw chuck 400 adopts alloy steel clamping jaw, which fixes the gear 500 through hydraulic clamping method, which can ensure clamping stability and avoid damage to the gear surface, and the eddy current sensor 600 is selected as high-frequency induction type, installed on the sensor bracket on the top of the fixed base 200, which can quickly identify the gear 500 material and provide data support for subsequent optical detection parameter adjustment, and the gantry 700 is made of aluminum alloy profile splicing, connected with the fixed base 200 through high-strength bolts, which not only reduces the overall weight, but also provides a stable mounting carrier for the confocal multi-modal optical assembly 800, ensuring the attitude accuracy during assembly displacement adjustment.

[0025] According to Figure 4 As shown in the figure, the confocal multi-modal optical assembly 800 further comprises a linear motor sliding table 801, the outer surface of the linear motor sliding table 801 is slidably connected with a first sliding block 802, the bottom of the first sliding block 802 is fixedly welded with a connecting plate 803, one side of the outer wall of the connecting plate 803 is bolted with a Z-axis linear module 804, and the Z-axis linear module 804 is used to provide vertical motion, the outer surface of the Z-axis linear module 804 is slidably connected with a second sliding block 805, one side of the outer wall of the second sliding block 805 is fixedly welded with an extension plate 806, the bottom of the extension plate 806 is fixedly connected with a flange plate 807, and the inner surfaces of the flange plate 807 are connected with the outer surface of the photomultiplier tube 829.

[0026] In the embodiment of the application, firstly, the linear motor sliding table 801 adopts a cast iron base combined with a stainless steel guide rail structure, is fixed on the beam of the gantry 700 through bolts, and is matched with a first sliding block 802 with a built-in precision ball screw, so that micron-level translation in the horizontal direction can be realized. The connecting plate 803 is made of 45 steel and is fixed with the first sliding block 802 through welding, so as to ensure the installation rigidity of the Z-axis linear module 804. Secondly, the Z-axis linear module 804 is driven by a servo motor, and the matched second sliding block 805 is loaded with a high-precision grating ruler, which can feedback the vertical displacement data in real time and accurately adapt to the detection height requirements of gears 500 of different sizes. Meanwhile, the extension plate 806 is made of aluminum alloy and is fixed with the second sliding block 805 through bolts. The flange plate 807 at the bottom is made of 304 stainless steel and is inserted into the mounting groove on the outer surface of the photomultiplier tube 829, which not only ensures stable connection, but also facilitates disassembly and maintenance in the later stage. This electrically adjusted mode replaces the traditional manual adjustment mode, which can greatly shorten the module alignment time and improve the detection efficiency in the batch gear detection scene.

[0027] According to Figure 7 and Figure 9 It is shown that the bottom of the flange plate 807 is connected with an optical seat 808, and the optical seat 808 is used to forcibly coaxial three light paths of laser, terahertz and fluorescence. The inner surface of the optical seat 808 is fixedly connected with an annular fixing ring 809, the bottom of the annular fixing ring 809 is connected with the top of an annular LED lamp 810, the inner surface of the optical seat 808 is symmetrically connected with sliding rails 811, the inner surface walls of the two sliding rails 811 are connected with sliding plates 812, the two sliding plates 812 are connected through a cross frame, the top of the two sliding plates 812 is connected with four optical filters 813, the four optical filters 813 are four different wavelengths, one outer wall side of one sliding plate 812 is fixedly connected with a rack 814, and the outer wall side of the second sliding block 805 is bolted with a mounting seat 815.

[0028] In the embodiment of the present application, first, the optical seat 808 is integrally machined from an aviation aluminum alloy, with three pre-set optical path channels inside, and the mechanical structure forcibly aligns the laser, terahertz and fluorescence optical paths coaxially, which can solve the problem of optical path crosstalk in traditional multi-modal devices from the root, wherein the annular fixing ring 809 is made of stainless steel, fixed to the inner wall of the optical seat 808 by full welding, and the annular LED lamp 810 at the bottom is a high-brightness surface-mounted lamp bead, uniformly distributed on the annular substrate, which can emit stable excitation light to ensure uniform illumination of the tooth surface fluorescent agent. Secondly, the slide rail 811 is made of stainless steel, fixed to the inner wall of the optical seat 808 by bolts, and the matching slide plate 812 is internally provided with wear-resistant sliding blocks to achieve smooth sliding. At the same time, the four optical filters 813 correspond to different wavelengths of optical channels, fixed to the slide plate 812 by clamping slots, which is convenient for later replacement and maintenance. The rack 814 is made of 45 steel rack, fixed to the slide plate 812 by welding, wherein the mounting seat 815 is made of aluminum alloy, then connected to the second sliding block 805 by bolts, which can provide a mounting basis for the subsequent transmission structure.

[0029] According to Figures 5-6 and Figure 10 , the top of the mounting seat 815 is fixedly provided with a micro motor 816, the shaft end of the micro motor 816 is rotatably connected with a transmission spur gear 817, the outer wall of the transmission spur gear 817 is meshingly connected with the outer wall of the rack 814, the outer surfaces of the optical seat 808 are connected with the outer surfaces of a terahertz emitter 818 and a terahertz receiver 821, and the inner surface of the optical seat 808 is connected with a first collimating mirror 819 through an adjustable support. The first collimating mirror 819 is in a parabolic shape.

[0030] In the embodiment of the present application, first, the micro motor 816 at the top of the mounting seat 815 is a stepping motor, fixedly installed by bolts, and the transmission spur gear 817 at the shaft end of the micro motor 816 is made of alloy steel and is subjected to carburizing quenching treatment, which can realize precise positioning of the optical filter 813 when meshing with the rack 814. The terahertz emitter 818 and the terahertz receiver 821 are compactly packaged and fixed in the mounting holes of the optical seat 808 by threads, and are oppositely arranged to ensure the stability of the detection signal. Secondly, the first collimating mirror 819 is made of parabolic optical glass and connected to the inner wall of the optical seat 808 through an adjustable support. The fine adjustment structure of the support can accurately adjust the angle of the collimating mirror, convert the divergent wave emitted by the terahertz emitter 818 into a parallel straight wave, effectively improve the signal strength and detection depth of the subsurface crack detection, and significantly reduce the propagation loss of the terahertz wave and improve the recognition accuracy of the subsurface crack.

[0031] According to Figures 7-8 and Figure 11As shown, the first collimating mirror 819 is used to change the divergent wave emitted by the terahertz transmitter 818 into parallel straight wave, the emitting end of the terahertz transmitter 818 is opposite to the first collimating mirror 819, the inner surface of the optical seat 808 is screw-connected with the first focusing objective 820, and the first focusing objective 820 is designed to be inclined downward by forty-five degrees, the receiving end of the terahertz receiver 821 is opposite to the first focusing objective 820, and the first focusing objective 820 is used to converge the terahertz wave reflected from the internal crack of the gear 500, the annular groove is arranged in the wall thickness of the optical seat 808, and the inner surface of the annular groove is connected with the outer surface of the laser transmitter 822, the inner surface of the optical seat 808 is connected with the first turning mirror 823 and the second turning mirror 826, and the laser emitting end of the laser transmitter 822 is opposite to the first turning mirror 823.

[0032] In the embodiment of the application, first, the first focusing objective 820 is made of achromatic optical glass, is installed on the objective seat of the inner wall of the optical seat 808 by forty-five degrees, can efficiently converge the terahertz wave reflected from the internal crack of the gear 500, and improves the signal receiving efficiency of the terahertz receiver 821, the annular groove in the wall thickness of the optical seat 808 provides a compact installation space for the laser transmitter 822, the laser transmitter 822 selects a 635nm semiconductor laser, is fixed in the annular groove by screwing, and the emitting end of the laser transmitter 822 is aligned with the first turning mirror 823, secondly, the first turning mirror 823 and the second turning mirror 826 are both made of high-reflectivity quartz glass, are installed on the mirror support inside the optical seat 808 by forty-five degrees, and the fine adjustment knob of the support can accurately adjust the angle of the mirror, so that the laser light path can be turned twice, the laser can be accurately focused to the gear surface detection area along the central axis direction, and the installation space of the piezoelectric feedback loading assembly 900 can be skillfully avoided, thereby solving the space conflict problem of multiple modules.

[0033] According to Figure 7 and Figure 12 As shown, the first turning mirror 823 and the second turning mirror 826 are both designed to be inclined downward by forty-five degrees, the second collimating mirror 824 and the second focusing objective 825 are screw-connected with the inner surface of the optical seat 808 respectively, the second collimating mirror 824 is arranged on the top of the second focusing objective 825, the second collimating mirror 824 is used to arrange the laser beam into parallel light, the second focusing objective 825 is used to focus the multiple parallel light into a tiny light spot, the mounting hole is arranged on the outer surface of the optical seat 808, the inner surface of the mounting hole and the outer surface of the pinhole diaphragm 827 are connected by being inserted, the photoelectric detector 828 is screw-connected with the outer surface of the optical seat 808, and the laser receiving end of the photoelectric detector 828 is opposite to the pinhole diaphragm 827.

[0034] In the embodiment of the present application, firstly, the second collimating mirror 824 is made of double-cemented optical glass material and is fixed in the lens barrel of the optical seat 808 through screw connection, which can arrange the divergent laser emitted by the laser emitter 822 into parallel light to provide a stable light beam basis for subsequent focusing, secondly, the second focusing objective 825 is selected from high numerical aperture optical lenses and is installed in the lens barrel below the second collimating mirror 824, which can condense the parallel laser into a small spot and ensure that the laser precisely acts on the crack area, thereby improving the resolution of crack size measurement, at the same time, the pinhole diaphragm 827 is made of stainless steel sheet material, a micro-hole is formed in the center of the pinhole diaphragm 827, and the pinhole diaphragm 827 is fixed in the mounting hole of the optical seat 808 through the insertion mode, the pinhole diaphragm 827 only allows the reflected light at the crack focus to pass through, which can effectively filter the non-focus stray light, and the photodetector 828 is selected from avalanche photodiodes and is fixed on the detector mounting seat of the optical seat 808 through bolts, the receiving end of the photodetector 828 is opposite to the pinhole diaphragm 827, which can quickly convert the optical signal into an electrical signal and can capture the dynamic changes of the crack in real time to provide high-quality data support for quantitative analysis.

[0035] According to Figures 14-16 As shown in the figure, the piezoelectric feedback loading assembly 900 further comprises an outer fixed sleeve 901, the top of the outer fixed sleeve 901 is threadedly connected with the bottom of the optical seat 808, the inner surfaces of the outer fixed sleeve 901 are connected with the outer surface of the annular pressure sensor 902, and a group of elastic clamping springs 903 are connected between the inner surfaces of the outer fixed sleeve 901 and are uniformly distributed along the circumference of the inner surface of the outer fixed sleeve 901.

[0036] In the embodiment of the present application, firstly, the outer fixed sleeve 901 is made of 7075 aluminum alloy material and is connected with the bottom of the optical seat 808 through screw connection, which can realize the integrated assembly of the piezoelectric feedback loading assembly 900 and the confocal multi-modal optical assembly 800, the annular pressure sensor 902 is selected from strain gauge sensors and is fixed on the inner wall of the outer fixed sleeve 901 through epoxy glue, which can monitor the total loading force acting on the tooth surface in real time, the group of elastic clamping springs 903 are made of beryllium bronze material and are uniformly distributed along the circumference of the inner surface of the outer fixed sleeve 901 and are fixed through clamping grooves, the elastic characteristics of the elastic clamping springs 903 can fix the middle piezoelectric ring 904 while absorbing the slight vibration generated during the loading process, thereby ensuring the posture stability of the middle piezoelectric ring 904 and avoiding the influence of vibration on the micron-level displacement output accuracy of the middle piezoelectric ring 904.

[0037] According to Figures 16-17 As shown in the figure, the inner surfaces of the group of elastic clamping springs 903 are connected with the middle piezoelectric ring 904, the inner surface of the middle piezoelectric ring 904 is fixedly connected with one side of the outer wall of the three micro-displacement sensors 906, and the three micro-displacement sensors 906 are arranged along the height of the middle piezoelectric ring 904.

[0038] In the embodiment of the application, first, the middle piezoelectric ring 904 adopts PZT-5H piezoelectric ceramic material, is fixed in the inner part of the outer fixed sleeve 901 through the elastic clamp spring 903, and can realize micron-level displacement output based on the piezoelectric effect, thereby providing a core driving force for precise crack opening. Three miniature displacement sensors 906 are selected as laser displacement sensors, are arranged uniformly along the height of the middle piezoelectric ring 904, are fixed on the inner wall of the middle piezoelectric ring 904 through buckles, can capture the instantaneous displacement mutation of crack opening in all directions, and can form a closed-loop control logic with the ring-shaped pressure sensor 902, so as to adjust and hover the loading force in real time according to the displacement signal. When the miniature displacement sensor 906 detects that the crack is opened to the preset size, a feedback signal is immediately fed back and the loading is stopped, thereby fundamentally solving the force control mismatch problem of the traditional static loading scheme, and taking into account the crack opening effect and tooth surface protection.

[0039] According to Figure 15 and Figure 18 , four grooves 905 are arranged at the bottom of the middle piezoelectric ring 904, and a threaded adapter seat 907 is connected between the inner walls of the four grooves 905. The bottom of the threaded adapter seat 907 is threadedly connected with a flexible loading head 908, the bottom of the flexible loading head 908 is embeddedly connected with the top of a miniature pressure sensor 909, and the bottom of the flexible loading head 908 is connected with a flexible contact pad 910.

[0040] In the embodiment of the application, the four grooves 905 at the bottom of the middle piezoelectric ring 904 provide installation space for the threaded adapter seat 907. The threaded adapter seat 907 is made of 304 stainless steel and is fixed to the inner wall of the groove 905 through epoxy glue. The inner thread at the bottom of the threaded adapter seat 907 cooperates with the outer thread of the flexible loading head 908, thereby successfully solving the assembly contradiction that the middle piezoelectric ring 904 cannot rotate. The flexible loading head 908 is made of polyurethane-silicon carbide composite material and has a hollow channel inside, which can ensure that the laser light path is unobstructed, realize interference-free cooperation between the loading action and optical detection, and the miniature pressure sensor 909 is selected as a miniature piezoresistive sensor and is embedded in the mounting hole at the bottom of the flexible loading head 908, which can accurately monitor the local contact force of the tooth surface. The flexible contact pad 910 is made of Shore 60A silicone material and is pasted to the bottom of the flexible loading head 908 through high-temperature resistant glue, which can reduce the rigid friction between the loading head and the tooth surface, protect the tooth surface, and ensure that the loading force is uniformly transmitted to the crack area.

[0041] In use, in the whole gear tooth surface crack optical nondestructive testing device working process, first of all, system initialization and gear parameter self recognition, at this time the operator fully gear clamped in three jaw chuck 400, motor index plate 300 driven gear 500 rotates to the initial zero position, at the same time fixed base 200 on the eddy current sensor 600 on the gear 500 non contact scanning, through the eddy current sensor 600 analysis eddy current effect difference automatic identification gear 500 material, and material information is sent to the central control system, then enter the detection parameter adaptive configuration stage, at this time the control system will be according to the material information drive micro motor 816, through the transmission spur gear 817 and rack 814 meshing drive slide plate 812 and its four installed on the light filter 813 on the slide rail 811 moves, the optimal wavelength of the filter 813 accurately switched to the light path in front of the photomultiplier tube 829, at the same time according to the material database preset piezoelectric feedback loading assembly 900 macro target load, immediately detection end positioning and focusing process, at this time the linear motor slide table 801 drive first slide block 802 and the whole detection end along the gear 500 tooth width direction positioning to the detection gear center, immediately Z axis linear module 804 drive second slide block 805 carrying optical seat 808 and piezoelectric feedback loading assembly 900 whole drop until the flexible contact pad 910 touch the tooth surface, when the annular pressure sensor 902 and micro pressure sensor 909 monitor the contact signal immediately lock position, in the core force light collaborative detection stage, piezoelectric feedback loading assembly 900 begins to execute intelligent loading process, at this time the middle layer piezoelectric ring 904 generates accurate displacement, and through the threaded adapter 907 and flexible loading head 908 on the tooth surface of the gear 500 exert linear incremental load, when three micro displacement sensor 906 capture the displacement mutation signal produced by the opening of the closed crack, the system immediately suspended current load, form the perception of closed crack, response adaptive trigger mechanism, at this time in the load suspension, confocal multimodal optical assembly 800 three channels synchronous start data acquisition work, first of all, using the ring LED lamp 810 emits ultraviolet excitation light makes the crack fluorescent agent luminescence, at this time the fluorescent signal is filtered by the light filter 813 and received by the photomultiplier tube 829 to generate surface crack image, then the wave emitted by the terahertz emitter 818 is collimated by the first 819 and penetrates the tooth surface, when the reflected signal of subsurface crack is converged by the first focusing objective 820 and received by the terahertz receiver 821;The laser emitted by the laser emitter 822 is twice turned and collimated and focused to form a light spot on the tooth surface of the gear 500, the reflected light is filtered by the pinhole diaphragm 827 and then received by the photodetector 828 to measure the three-dimensional topography, after single-point detection, the Z-axis linear module 804 will lift the detection end, while the linear motor sliding table 801 drives it to move to the next detection point to repeat the force-light cooperative detection, until the scanning of the complete tooth width is completed, the motor index plate 300 rotates by one tooth pitch angle to continue to detect the next tooth groove, finally the central control system performs time alignment and fusion analysis on all the multi-modal detection data of the tooth surface to generate a comprehensive quantitative diagnostic report containing the two-dimensional image of the crack, the three-dimensional topography size and the subsurface distribution, thereby effectively realizing the full-dimensional and high-precision nondestructive detection from the subsurface emerging defect to the working condition closed crack.

[0042] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can make modifications to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to part of the technical features, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A gear tooth surface crack optical non-destructive testing device, characterized in that: Support frame (100), confocal multimodal optical assembly (800), piezoelectric feedback loading assembly (900), the confocal multimodal optical assembly (800) and piezoelectric feedback loading assembly (900) are both installed on the top of support frame (100), and piezoelectric feedback loading assembly (900) is installed on the top of confocal multimodal optical assembly (800); The confocal multimodal optical assembly (800) comprises a ring LED lamp (810), a terahertz transmitter (818), a terahertz receiver (821), a laser transmitter (822), a pinhole diaphragm (827), and a photomultiplier tube (829), wherein the ring LED lamp (810) is used to emit excitation light to make the fluorescent agent at the crack emit light, the photomultiplier tube (829) is used to receive and amplify the fluorescent signal, the terahertz transmitter (818) and the terahertz receiver (821) are used for subsurface crack detection, and the pinhole diaphragm (827) is used to filter non-focal stray light. The piezoelectric feedback loading assembly (900) comprises a ring pressure sensor (902), a middle layer piezoelectric ring (904), three micro displacement sensors (906), and a micro pressure sensor (909), wherein the ring pressure sensor (902) is used to monitor the total loading force acting on the tooth surface in real time, the middle layer piezoelectric ring (904) is used to provide micron-level displacement output based on the piezoelectric effect, the three micro displacement sensors (906) are uniformly distributed along the circumference, the three micro displacement sensors (906) are used to capture the instantaneous displacement mutation of crack opening, and the micro pressure sensor (909) is used to monitor the local contact force of the tooth surface.

2. The optical non-destructive testing apparatus for gear tooth crack according to claim 1, characterized in that: The top of the support frame (100) is fixedly welded with a fixed base (200), the top of the fixed base (200) is provided with a motor dividing disc (300), the rotating end of the motor dividing disc (300) is rotationally connected with a three-jaw chuck (400), the top of the three-jaw chuck (400) is clamped and fixed with a gear (500), the top of the fixed base (200) is provided with an eddy current sensor (600), and the eddy current sensor (600) is used for material identification of the gear (500), and the top of the fixed base (200) is boltedly connected with a gantry (700).

3. The optical non-destructive testing apparatus for gear tooth crack according to claim 2, characterized in that: The confocal multimodal optical assembly (800) further comprises a linear motor sliding table (801), the outer surface of the linear motor sliding table (801) is slidingly connected with a first sliding block (802), the bottom of the first sliding block (802) is fixedly welded with a connecting plate (803), one side of the outer wall of the connecting plate (803) is boltedly connected with a Z-axis linear module (804), and the Z-axis linear module (804) is used to provide vertical movement, the outer surface of the Z-axis linear module (804) is slidingly connected with a second sliding block (805), one side of the outer wall of the second sliding block (805) is fixedly welded with an extension plate (806), the bottom of the extension plate (806) is fixedly connected with a flange plate (807), and the inner surfaces of the flange plate (807) are insertedly connected with the outer surfaces of the photomultiplier tubes (829).

4. The optical non-destructive testing apparatus for gear tooth crack according to claim 3, characterized in that: The bottom of the flange plate (807) is connected with an optical seat (808), and the optical seat (808) is used for forcing the coaxiality of three light paths of laser, terahertz and fluorescence, the inner surface of the optical seat (808) is fixedly connected with an annular fixing ring (809), the bottom of the annular fixing ring (809) is connected with the top of an annular LED lamp (810), the inner surface of the optical seat (808) is symmetrically connected with sliding rails (811), the inner surface walls of the two sliding rails (811) are both connected with sliding plates (812), the two sliding plates (812) are connected into one body through a cross beam, the top of the two sliding plates (812) is connected with four optical filters (813), the four optical filters (813) are of four different wavelengths, one outer wall side of one of the sliding plates (812) is fixedly connected with a rack (814), and the outer wall side of the second sliding block (805) is boltedly connected with a mounting seat (815).

5. The optical non-destructive testing apparatus for gear tooth crack according to claim 4, wherein: The top of the mounting seat (815) is fixedly provided with a micro motor (816), the shaft end of the micro motor (816) is rotatably connected with a transmission spur gear (817), the outer surface wall of the transmission spur gear (817) is meshedly connected with the outer surface wall of the rack (814), the outer surfaces of the optical seat (808) are connected with the outer surfaces of a terahertz emitter (818) and a terahertz receiver (821), respectively, the inner surface of the optical seat (808) is connected with a first collimating mirror (819) through an adjustable support, and the first collimating mirror (819) is of a parabolic shape.

6. The optical non-destructive testing apparatus for gear tooth crack according to claim 5, wherein: The first collimating mirror (819) is used for changing the divergent wave emitted by the terahertz emitter (818) into a parallel straight line wave, the emitting end of the terahertz emitter (818) faces the first collimating mirror (819), the inner surface of the optical seat (808) is boltedly connected with a first focusing objective lens (820), and the first focusing objective lens (820) is designed to be inclined downward by forty-five degrees, the receiving end of the terahertz receiver (821) faces the first focusing objective lens (820), and the first focusing objective lens (820) is used for converging the terahertz waves reflected from the internal crack of the gear (500), an annular groove is formed in the wall thickness of the optical seat (808), the inner surface of the annular groove is connected with the outer surface of a laser emitter (822), the inner surface of the optical seat (808) is connected with a first turning mirror (823) and a second turning mirror (826), and the laser emitting end of the laser emitter (822) faces the first turning mirror (823).

7. The optical non-destructive testing apparatus for gear tooth crack according to claim 6, wherein: The first turning mirror (823) and the second turning mirror (826) are both designed to be tilted downward by 45 degrees, a second collimating mirror (824) and a second focusing objective (825) are threadedly connected between the inner surfaces of the optical seat (808) respectively, and the second collimating mirror (824) is arranged on top of the second focusing objective (825), the second collimating mirror (824) is used for arranging the laser beam into parallel light, and the second focusing objective (825) is used for focusing the multiple parallel light into a micro light spot, the outer surface of the optical seat (808) is provided with a mounting hole, and the inner surface of the mounting hole and the outer surface of the pinhole diaphragm (827) are connected by being inserted, the outer surface of the optical seat (808) is boltedly connected with a photoelectric detector (828), and the laser receiving end of the photoelectric detector (828) is opposite to the pinhole diaphragm (827).

8. The optical non-destructive inspection apparatus for gear tooth crack according to claim 4, wherein: The piezoelectric feedback loading assembly (900) further comprises an outer fixing sleeve (901), the top of the outer fixing sleeve (901) is threadedly connected with the bottom of the optical seat (808), the inner surfaces of the outer fixing sleeve (901) are connected with the outer surface of the annular pressure sensor (902), a group of elastic clamping springs (903) are connected between the inner surfaces of the outer fixing sleeve (901), and the group of elastic clamping springs (903) are evenly distributed along the inner surface circumference of the outer fixing sleeve (901).

9. The optical non-destructive testing apparatus for gear tooth crack according to claim 8, characterized in that: The inner surfaces of the group of elastic clamping springs (903) are connected with the middle layer piezoelectric ring (904), the inner surface of the middle layer piezoelectric ring (904) is fixedly connected with one side of the outer wall of the three micro displacement sensors (906), and the three micro displacement sensors (906) are arranged along the height of the middle layer piezoelectric ring (904).

10. The optical non-destructive testing apparatus for gear tooth crack according to claim 9, wherein: Four grooves (905) are formed in the bottom of the middle layer piezoelectric ring (904), a threaded adapter seat (907) is connected between the inner walls of the four grooves (905), a flexible loading head (908) is threadedly connected to the bottom of the threaded adapter seat (907), the bottom of the flexible loading head (908) is embeddedly connected with the top of the micro pressure sensor (909), and the bottom of the flexible loading head (908) is connected with a flexible contact pad (910).

Images