A tooth breakage failure prevention method and device based on laser peening, a terminal device, and a storage medium

Abstract

This invention discloses a method, device, terminal equipment, and storage medium for preventing tooth breakage based on laser peening, belonging to the field of gear surface strengthening technology. The method involves: acquiring the pulsed laser parameters and impact path of the gear to be treated during laser peening; providing an energy absorption layer at the root of the gear tooth, which is covered by a constraint layer; generating a laser scanning command based on the pulsed laser parameters and impact path, and sending the laser scanning command to a laser generator to control the laser beam to scan, so that the laser beam penetrates the constraint layer and irradiates the energy absorption layer; after being irradiated, the energy absorption layer absorbs laser energy to form plasma, and the plasma generates an inwardly propagating shock wave under the constraint of the constraint layer, inducing plastic deformation at the gear tooth root position and forming a residual stress layer on the surface of the gear tooth root. Therefore, by implementing this invention, the problem of insufficient depth of the residual compressive stress layer on the tooth root surface in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of gear surface strengthening technology, and in particular to a method, device, terminal equipment and storage medium for preventing tooth breakage based on laser shot peening. Background Technology

[0002] In offshore wind power generation, the gearbox is a critical component of the offshore wind turbine. The gears in the gearbox operate under high loads, high salt spray, and rapid start-stop conditions for extended periods. Under these harsh and variable conditions, gear tooth breakage is a common occurrence. According to statistics from wind power companies, gear tooth breakage is a leading cause of malfunctions in offshore wind turbines, making its prevention crucial for ensuring the safe and stable operation of offshore wind turbines.

[0003] Existing technologies often employ mechanical shot peening, which uses a high-speed stream of cast steel shot or ceramic beads to impact the gear surface, creating numerous tiny pits that force the surface material to undergo plastic deformation, thereby generating a layer of residual compressive stress. However, due to the randomness of the impact angle and velocity of the high-speed shot, it is difficult to precisely target the gear tooth root, resulting in a shallow residual compressive stress layer. Therefore, there is a problem of insufficient depth of the residual compressive stress layer on the tooth root surface. Summary of the Invention

[0004] This invention provides a method, device, terminal equipment, and storage medium for preventing tooth breakage based on laser shot peening, which can solve the problem of insufficient depth of residual compressive stress layer on tooth root surface in the prior art.

[0005] The present invention provides a method for preventing tooth breakage based on laser peening, comprising: acquiring pulsed laser parameters and impact path when laser peening the gear to be treated; wherein, an energy absorption layer is provided at the tooth root position of the gear to be treated, and the surface of the energy absorption layer is covered with a light-transmitting constraint layer. A laser scanning command is generated based on the pulsed laser parameters and the impact path, and the laser scanning command is sent to the laser generator. After receiving the laser scanning command, the laser generator controls the laser beam to scan the energy absorption layer according to the pulsed laser parameters and the impact path, so that the laser beam passes through the constraint layer and irradiates the energy absorption layer. After being irradiated, the energy absorption layer absorbs laser energy to form plasma. Under the constraint of the constraint layer, the plasma generates an inwardly propagating shock wave, which induces plastic deformation at the root of the gear tooth and forms a residual stress layer on the surface of the gear tooth root.

[0006] Furthermore, the pulsed laser parameters include: wavelength, single pulse energy, frequency, and spot diameter; The wavelength is 1059 nanometers to 1069 nanometers; The single pulse energy is 100 millijoules to 500 millijoules; The frequency is from 50 Hz to 500 Hz; The diameter of the light spot is 0.2 mm to 0.5 mm.

[0007] Furthermore, the energy absorption layer is a black adhesive tape attached to the position of maximum curvature at the root of the gear.

[0008] Furthermore, the constraint layer is a water flow layer with a surface thickness of 2 mm, which is the energy absorption layer.

[0009] Furthermore, the generation of the impact path includes: Calculate the row spacing based on the spot diameter and the preset overlap rate; Determine the path boundary based on the geometry of the energy absorption layer; Several parallel lines are generated on the energy absorption layer according to the row spacing; Several parallel line segments are obtained by cutting several parallel lines according to the path boundary; Based on the rule of reverse parity, several parallel line segments are connected to generate an impact path.

[0010] Furthermore, it also includes: Obtain the hardness of the cross-section at the location of the residual stress layer and the hardness of the gear substrate; If the hardness of the cross section at the location of the residual stress layer is greater than the hardness of the gear substrate, the gear is considered to be in normal working condition. Otherwise, the gear is deemed to be in abnormal condition, and a fault message is generated.

[0011] Another embodiment of the present invention provides a tooth breakage prevention device based on laser shot peening, including: a scanning strategy formulation module and a laser control module; The scanning strategy formulation module is used to obtain the pulse laser parameters and impact path when the gear to be treated is laser peened; wherein, an energy absorption layer is provided at the tooth root position of the gear to be treated, and the surface of the energy absorption layer is covered with a light-transmitting constraint layer. The laser control module is used to generate a laser scanning command based on the pulsed laser parameters and the impact path, and send the laser scanning command to the laser generator. After receiving the laser scanning command, the laser generator controls the laser beam to scan the energy absorption layer according to the pulsed laser parameters and the impact path, so that the laser beam passes through the constraint layer and irradiates the energy absorption layer. After being irradiated, the energy absorption layer absorbs laser energy to form plasma. Under the constraint of the constraint layer, the plasma generates an inwardly propagating shock wave, which induces plastic deformation at the root of the gear tooth and forms a residual stress layer on the surface of the gear tooth root.

[0012] Furthermore, it also includes: a fault early warning module; The fault warning module is used to obtain the hardness of the cross section at the location of the residual stress layer and the hardness of the gear substrate. If the hardness of the cross section at the location of the residual stress layer is greater than the hardness of the gear substrate, the gear is considered to be in normal working condition. Otherwise, the gear is deemed to be in abnormal condition, and a fault message is generated.

[0013] Another embodiment of the present invention provides a terminal device, including: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the steps of the laser shot peening-based tooth breakage prevention method provided by the present invention.

[0014] Another embodiment of the present invention also provides a computer-readable storage medium item, including: a stored computer program, which, when the computer program is running, controls the device where the computer-readable storage medium is located to perform the steps of the laser shot peening-based tooth breakage prevention method provided by the present invention.

[0015] The following benefits can be obtained by implementing the present invention: This invention discloses a method for preventing tooth breakage based on laser shot peening. The method first performs overall cleaning of the gear surface to ensure that the subsequent energy absorption layer can firmly adhere to the tooth root surface. Then, laser shot peening is performed on the tooth root, and an energy absorption layer is placed at the tooth root to absorb laser energy and convert it into plasma. A constraint layer is then set on the surface of the energy absorption layer to limit the propagation direction of the shock wave generated by the plasma, so that the shock wave propagates inward and reduces impact energy loss. By setting the pulsed laser parameters and impact path, the laser generator scans the energy absorption layer. Under the action of the directional shock wave, high strain rate plastic deformation occurs on the tooth root surface, generating high-amplitude residual compressive stress on the surface, ultimately leaving a residual stress layer of sufficient depth. Compared with existing mechanical shot peening methods, because the laser beam and energy absorption layer can generate inward directional high-intensity shock waves under the action of the constraint layer, the resulting plastic deformation strain rate is higher, and the final residual stress layer on the tooth root surface is also deeper. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of a laser shot peening-based tooth breakage prevention method provided in an embodiment of the present invention. Figure 2This is a schematic diagram of a tooth breakage prevention device based on laser shot peening provided in an embodiment of the present invention; Figure 3 This is a partial sectional view of a gear provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of an energy absorption layer structure provided in an embodiment of the present invention; Figure 5 This is a curve showing the change in hardness with depth near the location of maximum curvature at the root of the gear after laser shot peening, provided by an embodiment of the present invention.

[0018] The labels in the attached figures are: 1 - the position of maximum curvature at the root of the gear. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0024] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0025] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0026] See Figure 1 To address the problem of insufficient depth of residual compressive stress layer on the tooth root surface in existing technologies, an embodiment of the present invention provides a method for preventing tooth breakage based on laser shot peening, comprising: 101. Obtain the pulsed laser parameters and impact path when performing laser shot peening on the gear to be treated; wherein, an energy absorption layer is provided at the tooth root position of the gear to be treated, and the surface of the energy absorption layer is covered with a light-transmitting constraint layer.

[0027] In a preferred embodiment, the pulsed laser parameters include: wavelength, single pulse energy, frequency, and spot diameter; The wavelength is 1059 nanometers to 1069 nanometers; The single pulse energy is 100 millijoules to 500 millijoules; The frequency is from 50 Hz to 500 Hz; The diameter of the light spot is 0.2 mm to 0.5 mm.

[0028] Wherein, wavelength refers to the laser wavelength, which is the physical distance between adjacent peaks when a pulsed laser propagates in a medium, characterizing the energy of laser photons and optical transmission characteristics, and is measured in nanometers (nm); single pulse energy refers to the total energy carried by a single laser pulse, characterizing the energy intensity of a single laser action, and is measured in millijoules (mJ); frequency refers to the pulse frequency, which is the number of pulses output by the laser generator per unit time, characterizing the time density and scanning efficiency of the laser impact, and is measured in hertz (Hz); and spot diameter refers to the size of the spot formed on the surface of the energy absorption layer after the laser beam is focused, characterizing the spatial range of a single laser impact, and is measured in millimeters (mm).

[0029] Specifically, the laser pulse parameters are obtained, including: wavelength of 1059 nm to 1069 nm (i.e., 1064 nm), with an allowable deviation of ±5 nm (1064 ± 5 ​​nm); single pulse energy of 100 mJ to 500 mJ (100 mJ to 500 mJ); frequency of 50 Hz to 500 Hz (50 Hz to 500 Hz); and spot diameter of 0.2 mm to 0.5 mm (0.2 mm to 0.5 mm).

[0030] The rationale for selecting the aforementioned laser pulse parameters is as follows: The fundamental frequency of the neodymium-doped yttrium aluminum garnet laser (Nd:YAG laser) is 1064 nm, while allowing a process tolerance of ±0.5%. The wavelength range of 1059 nm to 1069 nm falls within the near-infrared band. This band of laser possesses excellent optical transmittance and material coupling characteristics. On the one hand, it can efficiently penetrate transparent confinement layers such as water, optical glass, or K9 glass, reducing energy absorption loss within the confinement layer and ensuring that most of the laser energy reaches the energy absorption layer and achieves energy conversion. On the other hand, the near-infrared band and the metal substrate... Commonly used energy-absorbing layers such as black paint, aluminum foil, and black tape have high energy coupling efficiency, which can quickly excite plasma formation without causing excessive ablation of the surface layer. If the wavelength is too short, it is easily absorbed by the confinement layer or photo-induced breakdown, resulting in a decrease in effective impact energy. If the wavelength is too long, the photon energy is too low, the plasma excitation efficiency is insufficient, and the shock wave pressure is insufficient to produce effective plastic deformation at the tooth root. Therefore, the 1064±5nm range is selected to balance transmittance, coupling efficiency, and process stability, providing a stable energy input for the construction of the tooth root residual stress layer. In this method, the single-pulse energy ranges from 100 mJ to 500 mJ. The single-pulse energy directly determines the peak temperature, pressure, and shock wave amplitude of the plasma. When the energy is too low, the energy absorption layer vaporizes insufficiently, the plasma pressure is insufficient, and the gear root material cannot undergo plastic yielding, making it difficult to form an effective residual compressive stress layer. When the energy is too high, the plasma will expand excessively, and may even cause thermal damage such as ablation, microcracks, and molten recasting layers on the root surface, which will reduce the fatigue strength of the root and increase the risk of tooth breakage. This single-pulse energy range can form controllable plastic deformation at the critical section of the root, introducing a uniform and appropriately deep residual compressive stress field into the surface layer, offsetting the alternating tensile stress during gear meshing, inhibiting crack initiation and propagation, and thus preventing tooth breakage. At the same time, this energy range is compatible with the mechanical response characteristics of conventional gear materials such as tempered steel and carburized quenched steel, avoiding over-spraying and under-spraying problems, and is especially suitable for gears made of 18CrNiMo7 material. In this method, the frequency is set between 50 Hz and 500 Hz. The frequency determines the number of impact points per unit time and the cumulative strengthening effect on the tooth root surface. If the frequency is too low, the spacing between impact points will be too large, the residual stress distribution will be discontinuous, and the local area of ​​the tooth root will not be effectively strengthened, still posing a risk of tooth breakage. If the frequency is too high, the time interval between adjacent pulses will be too short, and the thermal effect and plastic wave generated by the preceding impact will not be fully dissipated, which will easily cause heat accumulation and stress superposition, leading to overheating, softening, or even microscopic defects on the material surface. This frequency range can achieve efficient and uniform shot peening while ensuring full coverage strengthening of the tooth root, making the residual stress layer continuous and dense, and will not damage the microstructure of the tooth root due to heat accumulation. This frequency range takes into account both processing efficiency and mechanical property stability, and is suitable for precision strengthening of complex tooth profiles and tooth root transition surfaces of gears. In this method, the laser spot diameter is controlled between 0.2 mm and 0.5 mm. The gear tooth root is a transition arc region with a small radius of curvature, which is confined in space and has significant stress concentration. The size of the laser spot directly affects the matching of the impact area and the uniformity of the stress field. If the laser spot diameter is too large, the laser action area will exceed the critical section of the tooth root, causing unnecessary impact on the non-strengthened area of ​​the tooth surface, and even damaging the tooth surface accuracy. On the other hand, if the laser spot diameter is too small, the impact area will be too concentrated, easily forming a local area with excessive stress, and the scanning path coverage efficiency will be low, making it difficult to achieve uniform strengthening of the entire tooth root. This method selects a smaller laser spot range to accurately match the geometric features of the transition arc of the tooth root, achieving targeted strengthening of the critical section, forming a continuous and gently gradient residual compressive stress layer in a limited area, significantly improving the bending fatigue strength of the tooth root, and inhibiting tooth breakage failure caused by fatigue crack propagation from the source.

[0031] In another preferred embodiment, the energy absorption layer is a black tape attached to the position of maximum curvature at the root of the gear.

[0032] The energy absorption layer is a functional coating pre-attached to the surface of the workpiece to be strengthened in laser peening. Its core function is to efficiently absorb pulsed laser energy and convert it into its constituent forms, providing the energy basis for the generation of shock waves. It is a key intermediate medium for surface strengthening in laser peening. Commonly used materials include black organic coatings, metal foils, polymer films, and graphite-carbon based materials. The energy absorption layer has the following functions: Energy absorption and conversion: After the laser beam passes through the light-transmitting confinement layer, it cannot be directly and efficiently absorbed by the gear metal substrate. The energy absorption layer can quickly absorb the laser energy and rapidly undergo vaporization and ionization reactions, converting the light energy into the thermal and kinetic energy of the plasma, providing an energy source for the subsequent generation of shock waves. Protection of the gear base: If the metal surface of the gear tooth root is directly irradiated by laser, it is easy to cause thermal damage such as ablation, melting, and microcracks in the metal surface layer, which will destroy the microstructure and surface precision of the tooth root and increase the risk of tooth breakage. The energy absorption layer can act as a buffer medium to absorb most of the laser energy, avoid the laser from directly acting on the gear base, and effectively protect the integrity of the tooth root surface. Enhancing Shock Wave Intensity: The plasma formed after the energy absorption layer absorbs energy cannot expand freely under the constraint of the confinement layer. It can only propagate directionally into the gear, thus forming a high-intensity shock wave. The absorption efficiency of the energy absorption layer directly determines the peak pressure of the plasma and the amplitude of the shock wave. It is a key prerequisite for ensuring that the tooth root produces effective plastic deformation and forms a residual stress layer, ultimately providing a guarantee for the prevention of tooth breakage.

[0033] Specifically, the surface of the gear to be treated is degreased and derusted, and black tape is applied to the position of maximum curvature at the root of the gear.

[0034] In this example, the partial sectional view of the gear is as follows: Figure 3 As shown, this includes: position 1 where the curvature at the root of the gear is at its maximum.

[0035] Furthermore, based on the partial sectional view of the gear, the structural schematic diagram of the energy absorption layer is as follows: Figure 4 As shown, the red area represents the black tape that serves as the energy absorption layer.

[0036] In this embodiment, by selecting black tape as the energy absorption layer, the energy absorption efficiency can be improved, which is suitable for process requirements. The black substrate of the black tape has a very strong absorption capacity for the near-infrared band (1059nm to 1069nm) laser selected in this method, with an absorption rate of over 90%. It can quickly convert laser energy into plasma energy, effectively avoid laser energy reflection or transmission, ensure that the shock wave intensity meets the requirements of tooth root plastic deformation, and provide stable energy support for the formation of residual stress layer. The tape has excellent adhesion and is suitable for complex curved surfaces at the tooth root. The gear tooth root is a transition arc structure with the largest curvature, with a narrow space and irregular surface. The black tape has good flexibility and adhesion, and can be tightly adhered to the stress concentration area with the largest curvature at the tooth root without wrinkles or gaps. This ensures the uniformity of energy absorption during laser impact and avoids insufficient local energy absorption due to poor adhesion. It ensures uniform reinforcement of the dangerous section of the tooth root and precisely addresses the risk of tooth breakage. Adhesive tape is inexpensive and easy to use, making it suitable for industrial applications. Black adhesive tape is readily available and extremely inexpensive. Compared to traditional energy absorption layers such as aluminum foil and black paint, it does not require complex coating and drying processes and can be directly cut to the size that matches the tooth root, quickly adhering to the target area. Compared to graphite carbon materials such as graphite sheets, carbon nanotube coatings, and graphene films, it is inexpensive and easy to prepare. Moreover, it can be easily peeled off after shot peening, leaving no residue and not damaging the surface precision of the tooth root, greatly reducing process costs and operational difficulty, making it suitable for industrial laser shot peening strengthening in gear mass production. Furthermore, under the pulsed laser parameters set in this method (100mJ to 500 mJ single pulse energy and 50Hz to 500 Hz frequency), the black tape will not experience abnormal phenomena such as premature detachment or burning. It can stably complete the energy absorption and conversion process, ensuring the continuity and stability of the laser shot peening process and guaranteeing the uniformity and consistency of the residual stress layer at the tooth root.

[0037] Furthermore, by selecting tapes of different thicknesses, the thickness of the energy absorption layer can be precisely controlled, thereby regulating the generation intensity of plasma and the amplitude of shock waves. This avoids excessive energy loss and insufficient shock wave intensity due to an excessively thick absorption layer, or damage to the gear base due to an excessively thin absorption layer, thus achieving precise and controllable plastic deformation of the tooth root and further improving the reliability of tooth breakage prevention.

[0038] In another preferred embodiment, the constraint layer is a water flow layer with a surface thickness of 2 mm on the energy absorption layer.

[0039] In laser peening, the constraint layer is a transparent functional medium covering the surface of the energy absorption layer. It needs to possess high transparency, high density, and a certain degree of mechanical constraint to limit the free expansion of plasma formed by the vaporization of the energy absorption layer under laser irradiation. It is a key process layer for controlling the intensity of the shock wave and ensuring the strengthening effect. Commonly used constraint layers include transparent solid constraint layers such as K9 glass, quartz glass, optical acrylic sheets, and sapphire sheets; flexible transparent constraint layers such as transparent PET film, PVC soft film, silicone transparent film, and optical adhesive film; and liquid constraint layers such as mineral oil, silicone oil, and anhydrous ethanol. The constraint layer has the following functions: Constraining plasma expansion enhances shock wave intensity: After absorbing laser energy, the energy absorption layer rapidly vaporizes and ionizes, forming high-temperature, high-pressure plasma. Without the constraint layer, the plasma would expand freely outwards, and the energy would diffuse rapidly, failing to form a shock wave of sufficient intensity. The constraint layer, through its density and inertia, prevents the plasma from expanding outwards, forcing it to propagate directionally into the gear root. This converts the plasma's thermal and kinetic energy into a high-intensity shock wave, ensuring that the shock wave amplitude is sufficient to cause plastic deformation of the gear root material, thus providing the power for the formation of the residual compressive stress layer. Cooling and protection to prevent surface damage: During laser peening, the vaporization of the energy absorption layer and the formation of plasma generate a large amount of heat. If the heat accumulates, it can easily lead to overheating and softening of the gear root surface, or even defects such as microcracks. The fluid confinement layer used in this method has excellent thermal conductivity, which can quickly remove excess heat from the laser action area, cool and protect the tooth root surface, prevent thermal damage, and prevent the energy absorption layer from burning or remaining, thus ensuring the precision of the tooth root surface and the integrity of the microstructure. Stable laser transmission ensures process uniformity: The constraint layer must have high light transmittance to ensure that the pulsed laser can penetrate efficiently without significant energy loss and accurately irradiate the surface of the energy absorption layer; the water flow layer, as a light-transmitting medium, can effectively reduce laser reflection and scattering, so that the laser energy can be applied evenly to the energy absorption layer, avoiding local energy concentration or insufficiency, ensuring uniform impact on the tooth root surface, and ultimately forming a continuous and uniform residual stress layer, improving the reliability of tooth breakage prevention.

[0040] Specifically, the circulating water system is turned on to form a 2-millimeter-thick flowing water film on the surface of the black tape.

[0041] In this embodiment, a 2 mm water flow layer is selected as the constraint layer, which can accurately match the shock wave intensity requirements and ensure the strengthening effect. The thickness of the water flow layer directly determines the strength of the constraint capability, thus affecting the shock wave amplitude. A 2 mm thick water flow layer can provide suitable inertial constraint, which can effectively block the free expansion of plasma, so that the shock wave intensity reaches the requirements of the tooth root material for plastic yielding, thereby ensuring the formation of a residual compressive stress layer of appropriate depth. However, it will not cause excessive constraint due to excessive thickness, resulting in excessive shock wave amplitude, causing excessive plastic deformation or microcracks on the tooth root surface. At the same time, it avoids insufficient constraint due to insufficient thickness, which would lead to shock wave energy diffusion and failure to achieve effective strengthening. It is particularly suitable for the laser parameters and tooth root strengthening requirements of this method. The water flow layer exhibits excellent light transmittance, reducing laser energy loss. For the near-infrared laser used in this method, the water flow layer provides excellent light transmittance, and a thickness of 2 mm falls within the optimal transmittance range of the water flow confinement layer. When the thickness is too thin, uneven water flow, the presence of air bubbles, or exposed areas can lead to laser reflection and scattering, increasing energy loss. Conversely, when the thickness is too thick, the laser travels a long distance in the water, resulting in energy attenuation due to water absorption, reducing the effective laser energy reaching the energy absorption layer. A thickness of 2 mm ensures efficient laser penetration, keeps energy loss within process requirements, and guarantees stable plasma generation in the energy absorption layer. The water flow layer provides even cooling, preventing the accumulation of heat damage. A 2mm water flow layer forms a stable liquid film covering the entire energy absorption layer surface. Its excellent thermal conductivity quickly removes heat generated by the laser, keeping the tooth root surface temperature within a safe range. This prevents the temperature from exceeding the tempering temperature of the gear material, effectively suppressing defects such as surface softening and ablation caused by heat accumulation. Simultaneously, the stable water flow film prevents uneven cooling, ensuring consistent microstructure across the tooth root after impact, further enhancing fatigue strength and reducing the risk of tooth breakage. Compared to flexible transparent constraint layers such as transparent PET film, PVC film, silicone transparent film, and optical adhesive film, which generally have lower high-temperature resistance and are prone to softening under high-energy lasers, the water flow layer exhibits better high-temperature resistance and stable physical properties under high-energy lasers. Furthermore, compared to liquid constraint layers such as mineral oil, silicone oil, and anhydrous ethanol, the water flow layer does not easily evaporate under high-energy lasers, offering better process stability. The fluid constraint layer adapts to the complex curved surface of the gear root, ensuring impact uniformity. The gear root is a transition arc structure with the largest curvature. The 2 mm thick water flow layer has good fluidity and conformity, which can adapt to the contour of the gear root surface and form a uniform liquid film coverage. This avoids local impact strength differences caused by uneven liquid film thickness, ensuring uniform reinforcement of the dangerous section area with the largest curvature at the gear root, accurately improving the fatigue resistance of this area, and preventing tooth breakage from the source. At the same time, the water flow layer of this thickness will not cause water flow turbulence due to being too thick, nor will it cause liquid film rupture due to being too thin, which can ensure the continuity and stability of the laser shot peening process. Compared with transparent solid constraint layers such as K9 glass, quartz glass, optical acrylic sheets, and sapphire sheets, which cannot adapt to curved surfaces and have poor conformity to complex arcs such as gear roots, the water flow layer can uniformly conform to the position with the largest curvature at the gear root. The operation of generating a water flow layer of preset thickness is convenient and suitable for industrial mass production; a water flow layer of 2 mm thickness can be achieved through simple spraying or overflow devices, the water flow pressure is easy to control, and a uniform and continuous liquid film can be formed without complicated preparation processes; moreover, the water flow can be recycled, which is inexpensive and suitable for the laser shot peening process in gear mass production.

[0042] In yet another preferred embodiment, the generation of the impact path includes: Calculate the row spacing based on the spot diameter and the preset overlap rate; Determine the path boundary based on the geometry of the energy absorption layer; Several parallel lines are generated on the energy absorption layer according to the row spacing; Several parallel line segments are obtained by cutting several parallel lines according to the path boundary; Based on the rule of reverse parity, several parallel line segments are connected to generate an impact path.

[0043] The overlap ratio is the ratio of the width of the overlapping portion of two adjacent laser spots to the diameter of a single spot, usually expressed as a percentage. The line spacing is the vertical distance between two adjacent parallel scan lines, and its size is determined by both the spot diameter and the overlap ratio. The odd-even row reversal rule, also known as the zigzag scanning strategy or bidirectional scanning strategy, has the following control logic: in odd-numbered rows, the laser beam is controlled to move from left to right in the X direction. After moving to the X-axis boundary, the Y-axis moves a distance equal to one line spacing to the even-numbered rows. In even-numbered rows, the laser beam is controlled to move from right to left in the X direction. That is, after scanning one line, it is not necessary to close the optical path or return to the X-axis starting point.

[0044] Specifically, based on the spot diameter and the preset overlap rate, the line spacing between adjacent scan lines is calculated. The formula for calculating the line spacing is as follows: ; In the formula, This is the line spacing; The diameter of the light spot; The overlap rate is set to 50% in this example. Based on the actual attachment position, size, and geometric contour of the energy absorption layer at the gear root, the effective boundary of the laser shock is defined. Referring to the shape of the black tape at the position of maximum curvature at the gear root in this embodiment, the path boundary is determined, with the edge of the black tape serving as the path boundary. Using the calculated row spacing as the interval, a series of parallel straight lines are generated within the energy absorption layer coverage area. These parallel straight lines are then trimmed according to the determined path boundary, removing segments that exceed the effective reinforcement area and retaining segments within the boundary, forming a series of discrete parallel impact segments with lengths matching the gear root contour. The trimmed parallel segments are then connected end-to-end according to an alternating pattern of odd and even row numbers, i.e., odd-numbered row segments are scanned in one direction, and even-numbered row segments are scanned in the opposite direction, sequentially connecting to form a continuous and non-reversible overall impact path.

[0045] In the above steps of generating the impact path, the preset overlap rate is used to ensure that the laser impact areas on the tooth root surface overlap and cover each other, avoiding unreinforced blank areas and making the residual stress distribution continuous and uniform. Then, by using the quantitative relationship between the spot size and the overlap rate, a reasonable row spacing can be determined, providing basic parameters for subsequent path layout. The path boundary strictly corresponds to the energy absorption layer and also corresponds to the position of maximum curvature at the gear root, which not only ensures full coverage reinforcement of high-risk areas of broken teeth, but also avoids unnecessary impacts caused by the laser exceeding the target area, preventing damage to tooth surface accuracy and meshing performance. The path planning method based on the odd-even row reversal rule can reduce the idle travel and galvanometer reversal time during the laser scanning process, improve processing efficiency, and at the same time ensure that the impact sequence is uniform and stable, avoiding uneven reinforcement due to local repeated impacts or excessively large intervals, and finally forming a continuous, stable and uniformly deep residual compressive stress layer on the tooth root surface. Furthermore, the path obtained through the above-mentioned impact path generation steps is a zigzag path. Compared to a unidirectional sequential path, where the laser head or galvanometer needs to quickly return to the starting point of the next row after completing one row of scanning, resulting in a large number of invalid idle strokes, this not only reduces processing efficiency but also easily causes impact timing fluctuations due to frequent start-stop cycles. The zigzag reciprocating path achieves continuous scanning without backtracking or jumping by continuously connecting odd and even rows in opposite directions, allowing the laser pulse to continuously act on the energy absorption layer, significantly reducing idle time and increasing the number of effective impact points per unit time, making it particularly suitable for gear batch strengthening scenarios. Meanwhile, unidirectional continuous scanning can cause the same area to be subjected to multiple continuous thermal effects in a short period of time, resulting in local temperature rise, material softening, and even expansion of the heat-affected zone; while the zigzag path with opposite odd and even rows can allow the impact areas of adjacent rows to be loaded alternately, giving the heat and plastic waves generated in the previous row sufficient time to diffuse, effectively suppressing heat accumulation and stress superposition, making the plastic deformation of the tooth root surface more uniform, the residual stress field gradient more gentle, and avoiding microcracks caused by local over-strengthening. Compared with ring paths and spiral paths, the zigzag parallel beam has higher geometric regularity, constant row spacing, and easy and precise control of the beam overlap rate. It will not cause excessive or insufficient overlap due to changes in the contour curvature. Compared with random dot matrix paths, reciprocating paths can achieve regular full coverage, with no missed spray areas, and can form a continuous and dense residual compressive stress layer at the dangerous section with the largest tooth root curvature. The reciprocating zigzag path has simple logic and low coordinate calculation requirements, and lower requirements for the motion control of the laser generator and scanning galvanometer. It can maintain a stable trajectory within the preferred frequency range of this invention (50Hz to 500Hz) and is less prone to step loss, lag or path deviation. Compared with complex curved paths, it has higher repeatability and better consistency of strengthening effect between different tooth roots, which is conducive to stable engineering applications.

[0046] Specifically, the surface of the 18CrNiMo7 gear to be treated is degreased and derusted to obtain a surface where the energy absorption layer can adhere firmly. Black tape is applied as an energy absorption layer at the position of maximum curvature at the gear root. Then, the water circulation system is turned on to form a 2mm water layer on the surface of the black tape as a constraint layer. The laser parameters for this laser peening are obtained, including: wavelength of 1064nm, pulse energy of 150mJ, frequency of 200Hz, and spot diameter of 0.2mm. The overlap rate is set to 50%, and the line spacing is calculated to be 0.1mm according to the line spacing calculation formula. The processing area is determined according to the shape of the black tape, and the outline of the black tape is extracted as the path boundary. Several parallel lines with an interval of 0.1mm are generated on the surface of the black tape according to the line spacing. Several parallel line segments are cut according to the path boundary. Then, based on the rule of odd and even rows being reversed, several parallel line segments are connected to generate a zigzag path, and the generated zigzag path is used as the impact path.

[0047] In the above scanning strategy formulation steps, the parameter combination of 1064 nm wavelength, 150 mJ single pulse energy, 200 Hz pulse frequency, and 0.2 mm spot diameter is set according to the material properties of the gear to be processed. This combination can generate a shock wave with moderate amplitude and controllable action time under the constraint of the flow flow layer, causing moderate plastic deformation of the tooth root surface layer and forming a residual compressive stress field with a gentle gradient and uniform distribution. This avoids surface ablation, excessive hardening, or insufficient strengthening caused by improper parameters. At the same time, the zigzag reciprocating impact path based on a 50% overlap rate and 0.1 mm row spacing can achieve full coverage of the tooth root strengthening area, with no missed sprays and no gaps, ensuring uniform overlap between adjacent impact points. The odd-even row reverse scanning method of the zigzag impact path effectively reduces idle stroke and heat accumulation, making the residual stress layer continuous and dense with small stress fluctuations, ultimately achieving precise and efficient strengthening of the stress concentration area of ​​the tooth root.

[0048] 102. A laser scanning command is generated based on the pulsed laser parameters and the impact path, and the laser scanning command is sent to the laser generator. After receiving the laser scanning command, the laser generator controls the laser beam to scan the energy absorption layer according to the pulsed laser parameters and the impact path, so that the laser beam passes through the constraint layer and irradiates the energy absorption layer. After being irradiated, the energy absorption layer absorbs laser energy to form plasma. Under the constraint of the constraint layer, the plasma generates an inwardly propagating shock wave, which induces plastic deformation at the root of the gear tooth and forms a residual stress layer on the surface of the gear tooth root.

[0049] Among them, the laser scanning command is used to control the laser generator to generate a laser beam according to the pulse laser parameters and to control the movement of the laser beam according to the impact path.

[0050] Specifically, based on preset pulsed laser parameters (wavelength 1064nm, single pulse energy 150mJ, frequency 200Hz, spot diameter 0.2mm) and the planned zigzag reciprocating impact path, motion control commands and laser trigger commands are fused and compiled to generate digital laser scanning commands that can be recognized and executed by the laser generator. These commands are then sent to the laser generator in real time via the control bus. Upon receiving the laser scanning command, the laser generator stably outputs a pulsed laser beam according to the pulse energy, repetition frequency, and timing requirements specified in the command. Simultaneously, the laser generator drives the laser beam to deflect based on the coordinate information of the impact path, enabling the laser beam to move precisely along the zigzag trajectory with a row spacing of 0.1mm and an overlap rate of 50%. This allows for continuous point-by-point and row-by-row scanning of the black tape energy absorption layer at the maximum curvature position at the gear root, ensuring that the laser beam always penetrates the 2mm thick water flow constraint layer and irradiates the energy absorption layer vertically. This achieves orderly, uniform, and full-coverage laser shot peening strengthening of the dangerous section at the gear root. When a high-power pulsed laser irradiates the black tape energy absorption layer on the metal surface, the energy absorption layer vaporizes and forms a high-temperature, high-pressure plasma. A water flow confinement layer covers the absorption layer, and the rapid expansion of the plasma is constrained by the inertia of the confinement layer, preventing it from expanding freely outward. This confinement causes the plasma pressure to rise sharply in a very short time, generating a pressure shock wave on the gear surface. This induces high-strain-rate plastic deformation at the maximum curvature position at the gear root, resulting in a residual compressive stress of about 300 MPa on the surface, followed by the formation of a residual stress layer with a depth of 1.0 mm.

[0051] In the aforementioned laser-controlled scanning steps, a stable, uniform, and depth-controllable residual compressive stress field can be formed at the critical section of the 18CrNiMo7 gear tooth root. This effectively counteracts the alternating bending tensile stress generated during gear meshing, significantly inhibiting the initiation and propagation of early microcracks. The residual stress layer near the maximum curvature of the gear root exhibits a 10% to 50% increase in Vickers hardness compared to the original gear substrate. After laser shot peening, the surface near the maximum curvature of the gear root is smooth and flat, free from defects such as voids and cracks. The mechanical properties of the gear itself are not diminished, and fatigue life is increased by more than 30%. The zigzag reciprocating scanning combined with a reasonable overlap rate achieves full-area, blind-zone-free strengthening, avoiding localized stress unevenness and thermal accumulation damage. Ultimately, this significantly improves the bending fatigue strength and load-bearing capacity of the tooth root, providing a significant and reliable preventive effect against gear tooth breakage failures under heavy-load conditions. After simple cleaning of the gear surface, it can be directly delivered to the standard gearbox assembly process. This gear surface strengthening process has low cost, high automation, and is suitable for continuous operation, meeting the needs of large-scale production and maintenance.

[0052] In a preferred embodiment, the laser-peening-based tooth breakage prevention method further includes: Obtain the hardness of the cross-section at the location of the residual stress layer and the hardness of the gear substrate; If the hardness of the cross section at the location of the residual stress layer is greater than the hardness of the gear substrate, the gear is considered to be in normal working condition. Otherwise, the gear is deemed to be in abnormal condition, and a fault message is generated.

[0053] In this embodiment, the hardness is Vickers hardness, which can be measured using a Vickers hardness tester.

[0054] Specifically, after laser shot peening and once the offshore wind turbines are operational, maintenance and monitoring personnel use a portable Vickers hardness tester to measure the hardness of the exposed cross-section at the gear root. The hardness of the cross-section at the residual stress layer location is then compiled and submitted along with the corresponding gear substrate hardness. By comparing the measured hardness of the cross-section at the residual stress layer location with the original hardness of the gear substrate, the degree of residual compressive stress in the gear root region is determined. If the Vickers hardness at the residual stress layer location is higher than the original hardness of the gear substrate, it indicates the presence of residual compressive stress, and the gear operation is considered safe. If it is lower than the original hardness of the gear substrate, it indicates an abnormal fault condition causing the surface residual compressive stress to disappear, placing the gear operation in an early risk warning state, and generating fault information.

[0055] In the aforementioned fault warning steps, after laser shot peening, the hardness of the cross-section where the residual stress layer at the gear tooth root is located is tested to obtain the hardness distribution value along the depth direction in this area, and the hardness of the unreinforced substrate area is used as a reference standard. The hardness of the cross-section at the residual stress layer location is compared with the hardness of the gear substrate. If the hardness of the cross-section at the residual stress layer location is significantly higher than the hardness of the gear substrate, it indicates that the tooth root material has undergone sufficient plastic deformation and grain refinement under the action of high-intensity shock waves, the surface work hardening effect is significant, and the residual compressive stress field is complete and stable. It can be determined that the gear reinforcement quality is qualified and the working condition is normal. Normally, if the cross-sectional hardness at the residual stress layer location does not meet the criteria for exceeding the hardness of the substrate, it indicates insufficient laser peening energy input, uneven impact path coverage, or the gear being in an abnormal operating condition. The tooth root has not formed an effective strengthening layer and the expected residual compressive stress distribution. This immediately determines the gear's operating condition is abnormal and automatically generates fault warning information, providing a basis for subsequent parameter optimization, rework strengthening, quality traceability, and fault early warning. This online hardness determination and operating condition verification process achieves quantitative and standardized detection of the laser peening strengthening effect, effectively screening out hidden quality defects such as insufficient strengthening and substandard stress layers, ensuring 18C... rNiMo7 gear teeth possess stable and sufficient surface hardness and fatigue resistance. Hardness differences directly reflect the degree of plastic deformation and the effectiveness of residual stress, allowing monitoring of contact impact stress and wear at critical sections of the tooth root under actual working conditions. For example, in humid marine environments, if gearbox seal failure leads to lubricant emulsification or oil film rupture, the tooth surfaces will transition from fluid lubrication to boundary lubrication or even dry friction. Intense friction generates instantaneous high temperatures. When these temperatures exceed the material's tempering temperature or even phase transformation temperature, the surface martensite decomposes, transforming into softer sorbite or ferrite, resulting in a significant decrease in hardness. The high salt spray environment at sea causes corrosion pits on the gear surface. As stress concentration points, corrosion not only directly damages the surface material but also leads to local stress concentration, accelerating fatigue crack initiation and causing premature failure of the reinforcement layer. Under long-term heavy-load operation, the microstructure of the gear surface material will evolve. Under cyclic contact stress, the residual compressive stress introduced by laser shot peening will gradually be released. When the compressive stress is completely released and transformed into tensile stress, the material's ability to resist deformation will decrease. The above-mentioned fault early warning steps further improve the reliability of tooth breakage prevention and the stability of gears in long-term service from the quality control level.

[0056] Schematic illustration: The hardness variation curve of the area near the maximum curvature at the root of the gear after laser shot peening, measured by Vickers hardness testing, is shown below. Figure 5 As shown, after laser shot peening, the hardness at the cross-section of the gear with a depth of 0.1 mm to 1 mm is significantly higher than the hardness at the internal cross-section of the gear.

[0057] By implementing the above embodiments, a method for preventing tooth breakage based on laser peening can be obtained. The surface of the gear to be treated can be strengthened by laser peening technology to obtain a residual stress layer of sufficient thickness to prevent tooth breakage. In addition, by detecting the hardness of the cross section at the location of the residual stress layer, it is possible to detect whether the working condition of the gear after laser peening is normal. If an abnormal working condition occurs, fault information is generated to avoid further losses.

[0058] like Figure 2 As shown, based on the above method embodiments, corresponding apparatus embodiments are provided; One embodiment of the present invention provides a tooth breakage prevention device based on laser shot peening, comprising: a scanning strategy formulation module and a laser control module; The scanning strategy formulation module is used to obtain the pulse laser parameters and impact path when the gear to be treated is laser peened; wherein, an energy absorption layer is provided at the tooth root position of the gear to be treated, and the surface of the energy absorption layer is covered with a light-transmitting constraint layer. In a preferred embodiment, the pulsed laser parameters include: wavelength, single pulse energy, frequency, and spot diameter; The wavelength is 1059 nanometers to 1069 nanometers; The single pulse energy is 100 millijoules to 500 millijoules; The frequency is from 50 Hz to 500 Hz; The diameter of the light spot is 0.2 mm to 0.5 mm.

[0059] Wherein, wavelength refers to the laser wavelength, which is the physical distance between adjacent peaks when a pulsed laser propagates in a medium, characterizing the energy of laser photons and optical transmission characteristics, and is measured in nanometers (nm); single pulse energy refers to the total energy carried by a single laser pulse, characterizing the energy intensity of a single laser action, and is measured in millijoules (mJ); frequency refers to the pulse frequency, which is the number of pulses output by the laser generator per unit time, characterizing the time density and scanning efficiency of the laser impact, and is measured in hertz (Hz); and spot diameter refers to the size of the spot formed on the surface of the energy absorption layer after the laser beam is focused, characterizing the spatial range of a single laser impact, and is measured in millimeters (mm).

[0060] Specifically, the laser pulse parameters are obtained, including: wavelength of 1059 nm to 1069 nm (i.e., 1064 nm), with an allowable deviation of ±5 nm (1064 ± 5 ​​nm); single pulse energy of 100 mJ to 500 mJ (100 mJ to 500 mJ); frequency of 50 Hz to 500 Hz (50 Hz to 500 Hz); and spot diameter of 0.2 mm to 0.5 mm (0.2 mm to 0.5 mm).

[0061] In another preferred embodiment, the energy absorption layer is a black tape attached to the position of maximum curvature at the root of the gear.

[0062] The energy absorption layer is a functional coating pre-attached to the surface of the workpiece to be strengthened in laser peening. Its core function is to efficiently absorb pulsed laser energy and convert it into its constituent forms, providing the energy basis for the generation of shock waves. It is a key intermediate medium for surface strengthening in laser peening. Commonly used materials include black organic coatings, metal foils, polymer films, and graphite-carbon based materials. The energy absorption layer has the following functions: Energy absorption and conversion: After the laser beam passes through the light-transmitting confinement layer, it cannot be directly and efficiently absorbed by the gear metal substrate. The energy absorption layer can quickly absorb the laser energy and rapidly undergo vaporization and ionization reactions, converting the light energy into the thermal and kinetic energy of the plasma, providing an energy source for the subsequent generation of shock waves. Protection of the gear base: If the metal surface of the gear tooth root is directly irradiated by laser, it is easy to cause thermal damage such as ablation, melting, and microcracks in the metal surface layer, which will destroy the microstructure and surface precision of the tooth root and increase the risk of tooth breakage. The energy absorption layer can act as a buffer medium to absorb most of the laser energy, avoid the laser from directly acting on the gear base, and effectively protect the integrity of the tooth root surface. Enhancing Shock Wave Intensity: The plasma formed after the energy absorption layer absorbs energy cannot expand freely under the constraint of the confinement layer. It can only propagate directionally into the gear, thus forming a high-intensity shock wave. The absorption efficiency of the energy absorption layer directly determines the peak pressure of the plasma and the amplitude of the shock wave. It is a key prerequisite for ensuring that the tooth root produces effective plastic deformation and forms a residual stress layer, ultimately providing a guarantee for the prevention of tooth breakage.

[0063] Specifically, the surface of the gear is degreased and derusted, and black tape is applied to the position of maximum curvature at the root of the gear.

[0064] In another preferred embodiment, the constraint layer is a water flow layer with a surface thickness of 2 mm on the energy absorption layer.

[0065] The constraint layer is a transparent functional medium covering the surface of the energy absorption layer in the laser shot peening process. It needs to have high light transmittance, high density and a certain mechanical constraint capability to restrict the free expansion of plasma formed by the vaporization of the energy absorption layer under the action of laser. It is a key process layer for controlling the intensity of shock waves and ensuring the strengthening effect. Commonly used constraint layers include transparent solid constraint layers such as K9 glass, quartz glass, optical acrylic sheet, and sapphire sheet; flexible transparent constraint layers such as transparent PET film, PVC soft film, silicone transparent film, and optical film; and liquid constraint layers such as mineral oil, silicone oil, and anhydrous ethanol.

[0066] Specifically, the circulating water system is turned on to form a 2-millimeter-thick flowing water film on the surface of the black tape.

[0067] In yet another preferred embodiment, the generation of the impact path includes: Calculate the row spacing based on the spot diameter and the preset overlap rate; Determine the path boundary based on the geometry of the energy absorption layer; Several parallel lines are generated on the energy absorption layer according to the row spacing; Several parallel line segments are obtained by cutting several parallel lines according to the path boundary; Based on the rule of reverse parity, several parallel line segments are connected to generate an impact path.

[0068] The overlap ratio is the ratio of the width of the overlapping portion of two adjacent laser spots to the diameter of a single spot, usually expressed as a percentage. The line spacing is the vertical distance between two adjacent parallel scan lines, and its size is determined by both the spot diameter and the overlap ratio. The odd-even row reversal rule, also known as the zigzag scanning strategy or bidirectional scanning strategy, has the following control logic: in odd-numbered rows, the laser beam is controlled to move from left to right in the X direction. After moving to the X-axis boundary, the Y-axis moves a distance equal to one line spacing to the even-numbered rows. In even-numbered rows, the laser beam is controlled to move from right to left in the X direction. That is, after scanning one line, it is not necessary to close the optical path or return to the X-axis starting point.

[0069] Specifically, the surface of the 18CrNiMo7 gear to be treated is degreased and derusted to obtain a surface where the energy absorption layer can adhere firmly. Black tape is applied as an energy absorption layer at the position of maximum curvature at the gear root. Then, the water circulation system is turned on to form a 2mm water layer on the surface of the black tape as a constraint layer. The laser parameters for this laser peening are obtained, including: wavelength of 1064nm, pulse energy of 150mJ, frequency of 200Hz, and spot diameter of 0.2mm. The overlap rate is set to 50%, and the line spacing is calculated to be 0.1mm according to the line spacing calculation formula. The processing area is determined according to the shape of the black tape, and the outline of the black tape is extracted as the path boundary. Several parallel lines with an interval of 0.1mm are generated on the surface of the black tape according to the line spacing. Several parallel line segments are cut according to the path boundary. Then, based on the rule of odd and even rows being reversed, several parallel line segments are connected to generate a zigzag path, and the generated zigzag path is used as the impact path.

[0070] The aforementioned scanning strategy formulation module sets a parameter combination of 1064 nm wavelength, 150 mJ single pulse energy, 200 Hz pulse frequency, and 0.2 mm spot diameter for the material properties of the gear to be processed. This combination can generate a shock wave with moderate amplitude and controllable action time under the constraint of the flow flow layer, causing moderate plastic deformation of the tooth root surface layer and forming a residual compressive stress field with a gentle gradient and uniform distribution. This avoids surface ablation, over-hardening, or insufficient strengthening caused by improper parameters. At the same time, the zigzag reciprocating impact path planned based on a 50% overlap rate and 0.1 mm row spacing can achieve full coverage of the tooth root strengthening area, with no missed sprays and no gaps, ensuring uniform overlap between adjacent impact points. The odd-even row reverse scanning method of the zigzag impact path effectively reduces idle stroke and heat accumulation, making the residual stress layer continuous and dense with small stress fluctuations, ultimately achieving precise and efficient strengthening of the stress concentration area of ​​the tooth root.

[0071] The laser control module is used to generate a laser scanning command based on the pulsed laser parameters and the impact path, and send the laser scanning command to the laser generator. After receiving the laser scanning command, the laser generator controls the laser beam to scan the energy absorption layer according to the pulsed laser parameters and the impact path, so that the laser beam passes through the constraint layer and irradiates the energy absorption layer. After being irradiated, the energy absorption layer absorbs laser energy to form plasma. Under the constraint of the constraint layer, the plasma generates an inwardly propagating shock wave, which induces plastic deformation at the root of the gear tooth and forms a residual stress layer on the surface of the gear tooth root.

[0072] Among them, the laser scanning command is used to control the laser generator to generate a laser beam according to the pulse laser parameters and to control the movement of the laser beam according to the impact path.

[0073] Specifically, based on preset pulsed laser parameters (wavelength 1064nm, single pulse energy 150mJ, frequency 200Hz, spot diameter 0.2mm) and the planned zigzag reciprocating impact path, motion control commands and laser trigger commands are fused and compiled to generate digital laser scanning commands that can be recognized and executed by the laser generator. These commands are then sent to the laser generator in real time via the control bus. Upon receiving the laser scanning command, the laser generator stably outputs a pulsed laser beam according to the pulse energy, repetition frequency, and timing requirements specified in the command. Simultaneously, the laser generator drives the laser beam to deflect based on the coordinate information of the impact path, enabling the laser beam to move precisely along the zigzag trajectory with a row spacing of 0.1mm and an overlap rate of 50%. This allows for continuous point-by-point and row-by-row scanning of the black tape energy absorption layer at the maximum curvature position at the gear root, ensuring that the laser beam always penetrates the 2mm thick water flow constraint layer and irradiates the energy absorption layer vertically. This achieves orderly, uniform, and full-coverage laser shot peening strengthening of the dangerous section at the gear root. When a high-power pulsed laser irradiates the black tape energy absorption layer on the metal surface, the energy absorption layer vaporizes and forms a high-temperature, high-pressure plasma. A water flow confinement layer covers the absorption layer, and the rapid expansion of the plasma is constrained by the inertia of the confinement layer, preventing it from expanding freely outward. This confinement causes the plasma pressure to rise sharply in a very short time, generating a pressure shock wave on the gear surface. This induces high-strain-rate plastic deformation at the maximum curvature position at the gear root, resulting in a residual compressive stress of about 300 MPa on the surface, followed by the formation of a residual stress layer with a depth of 1.0 mm.

[0074] The aforementioned laser control module can form a stable, uniform, and depth-controllable residual compressive stress field at the critical section of the 18CrNiMo7 gear tooth root, effectively counteracting the alternating bending tensile stress generated during gear meshing and significantly suppressing the initiation and propagation of early microcracks. The residual stress layer near the maximum curvature at the gear root exhibits a 10% to 50% increase in Vickers hardness compared to the original gear substrate. After laser shot peening, the surface near the maximum curvature at the gear root is smooth and flat, free of voids and cracks, without any degradation in the gear's mechanical properties, and its fatigue life is increased by more than 30%. The zigzag reciprocating scanning combined with a reasonable overlap rate achieves full-area, blind-zone-free strengthening, avoiding localized stress unevenness and thermal accumulation damage, ultimately significantly improving the bending fatigue strength and load-bearing capacity of the tooth root, providing a significant and reliable preventative effect against gear tooth breakage under heavy-load conditions. Subsequent simple cleaning of the gear surface allows for direct delivery to standard gearbox assembly processes. This gear surface strengthening process is low-cost, highly automated, suitable for continuous operation, and meets the needs of large-scale production and maintenance.

[0075] In a preferred embodiment, the laser shot peening-based tooth breakage prevention device further includes: a fault early warning module; The fault warning module is used to obtain the hardness of the cross section at the location of the residual stress layer and the hardness of the gear substrate. If the hardness of the cross section at the location of the residual stress layer is greater than the hardness of the gear substrate, the gear is considered to be in normal working condition. Otherwise, the gear is deemed to be in abnormal condition, and a fault message is generated.

[0076] It is understood that the above-described device embodiments correspond to the method embodiments of the present invention, and can realize the laser shot peening-based tooth breakage prevention method provided by any of the above-described method embodiments of the present invention.

[0077] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can specifically be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0078] Based on the above embodiments of the laser peening-based tooth breakage prevention method, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the laser peening-based tooth breakage prevention method of any embodiment of the present invention.

[0079] For example, in this embodiment, the computer program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the terminal device.

[0080] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0081] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0082] Based on the above-described method embodiments, another embodiment of the present invention provides a computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute the laser shot peening-based tooth breakage prevention method described in any of the above-described method embodiments of the present invention.

[0083] The modules / units integrated in the device / terminal equipment, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0084] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A tooth breakage failure prevention method based on laser peening, characterized by, include: The pulsed laser parameters and impact path are obtained when the gear to be treated is laser peened; wherein, an energy absorption layer is provided at the tooth root position of the gear to be treated, and the surface of the energy absorption layer is covered with a light-transmitting constraint layer. A laser scanning command is generated based on the pulsed laser parameters and the impact path, and the laser scanning command is sent to the laser generator. After receiving the laser scanning command, the laser generator controls the laser beam to scan the energy absorption layer according to the pulsed laser parameters and the impact path, so that the laser beam passes through the constraint layer and irradiates the energy absorption layer. After being irradiated, the energy absorption layer absorbs laser energy to form plasma. Under the constraint of the constraint layer, the plasma generates an inwardly propagating shock wave, which induces plastic deformation at the root of the gear tooth and forms a residual stress layer on the surface of the gear tooth root.

2. The laser peening based tooth breakage prevention method according to claim 1, wherein, The pulsed laser parameters include: wavelength, single pulse energy, frequency, and spot diameter; The wavelength is 1059 nanometers to 1069 nanometers; The single pulse energy is 100 millijoules to 500 millijoules; The frequency is from 50 Hz to 500 Hz; The diameter of the light spot is 0.2 mm to 0.5 mm.

3. The laser peening based tooth breakage prevention method according to claim 2, wherein, The energy absorption layer is a black tape attached to the root of the gear at the position of maximum curvature.

4. The laser peening based tooth breakage prevention method according to claim 3, wherein, The constraint layer is a water flow layer with a surface thickness of 2 mm, which is the energy absorption layer.

5. The laser peening based tooth breakage prevention method according to claim 4, wherein, The generation of the impact path includes: Calculate the row spacing based on the spot diameter and the preset overlap rate; Determine the path boundary based on the geometry of the energy absorption layer; Several parallel lines are generated on the energy absorption layer according to the row spacing; Several parallel line segments are obtained by cutting several parallel lines according to the path boundary; Based on the rule of reverse parity, several parallel line segments are connected to generate an impact path.

6. The laser peening based tooth breakage prevention method according to claim 5, wherein, Also includes: Obtain the hardness of the cross-section at the location of the residual stress layer and the hardness of the gear substrate; If the hardness of the cross section at the location of the residual stress layer is greater than the hardness of the gear substrate, the gear is considered to be in normal working condition. Otherwise, the gear is deemed to be in abnormal condition, and a fault message is generated.

7. A tooth breakage prevention device based on laser peening characterized by, include: Scanning strategy formulation module and laser control module; The scanning strategy formulation module is used to obtain the pulse laser parameters and impact path when the gear to be treated is laser peened; wherein, an energy absorption layer is provided at the tooth root position of the gear to be treated, and the surface of the energy absorption layer is covered with a light-transmitting constraint layer. The laser control module is used to generate a laser scanning command based on the pulsed laser parameters and the impact path, and send the laser scanning command to the laser generator. After receiving the laser scanning command, the laser generator controls the laser beam to scan the energy absorption layer according to the pulsed laser parameters and the impact path, so that the laser beam passes through the constraint layer and irradiates the energy absorption layer. After being irradiated, the energy absorption layer absorbs laser energy to form plasma. Under the constraint of the constraint layer, the plasma generates an inwardly propagating shock wave, which induces plastic deformation at the root of the gear tooth and forms a residual stress layer on the surface of the gear tooth root.

8. The laser peening based tooth breakage prevention apparatus of claim 7, wherein, Also includes: Fault early warning module; The fault warning module is used to obtain the hardness of the cross section at the location of the residual stress layer and the hardness of the gear substrate. If the hardness of the cross section at the location of the residual stress layer is greater than the hardness of the gear substrate, the gear is considered to be in normal working condition. Otherwise, the gear is deemed to be in abnormal condition, and a fault message is generated.

9. A terminal device, comprising: The method includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, it implements the laser peening-based tooth breakage prevention method as described in any one of claims 1-6.

10. A computer-readable storage medium, characterized in that, include: A stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform the laser peening-based tooth breakage prevention method as described in any one of claims 1-6.

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