34 results about "Contact fatigue" patented technology

The present application belongs to the field of rail material research and manufacturing, and specifically discloses a rail structure for a subway humid environment. According to the distribution of pearlite lamellar spacing, the rail head cross-section structure can be divided into cap layer 1, cap layer 2, cap layer 3 and base material layer. The pearlite lamellar spacing distribution of cap layer 1 is 130-150 nm, the pearlite lamellar spacing distribution of cap layer 2 is 90-120 nm, the pearlite lamellar spacing distribution of cap layer 3 is 140-170 nm, and the pearlite lamellar spacing distribution of the base material layer is 200-230 nm. The present application designs cap-shaped structures with different depths and different pearlite lamellar spacing in the rail head. By accelerating the cooling speed of the heat treatment of the hot-rolled rail in different stages, the reasonable gradient structure distribution of the pearlite structure of the rail material is realized, the expansion speed of the rolling contact fatigue crack of the rail in the humid environment to the internal material is effectively slowed down, the rolling contact fatigue damage is reduced, and thus the comprehensive performance and service life of the rail are improved.

The invention discloses a time-varying reliability optimization design method and system for a helical gear. The method comprises the following steps: establishing a gear reliability optimization design model which takes gear volume minimization as an optimization target and takes full-life-cycle time-varying reliability as a constraint; constructing a gear contact fatigue time-varying limit state function coupling the time-varying load spectrum and the material strength degradation model; constructing a time-varying reliability analysis module based on an agent model and an active learning strategy so as to evaluate the time-varying limit state function; and an optimization algorithm is adopted to solve the gear reliability optimization design model, the time-varying failure probability of the candidate scheme is evaluated by calling the time-varying reliability analysis module, the time-varying reliability constraint is processed according to the time-varying failure probability, and optimal gear design parameters meeting the constraint are output. According to the method, efficient cooperation of time-varying reliability high-precision evaluation and lightweight optimization design is realized, and the problem that a time-varying factor cannot be considered in optimization due to too high analysis cost in a traditional method is solved.

This invention provides a single-rod, dual-pump synchronously driven, alternating, continuous, ultra-low alternating load deep pumping lifting system, comprising a double-rod working cylinder, at least one set of gear assembly supports, and two parallel-arranged pumps. The upper end of the gear assembly supports is connected to the double-rod working cylinder, and the lower end is connected to the two parallel-arranged pumps via double-pump couplings. Two parallel rack rods are provided inside the working cylinder, and the lower ends of the two rack rods are connected to the plungers of the two pumps respectively. Racks for meshing with gears installed in the gear assembly supports are fixed on the two rack rods. Flow holes are provided on the gear assembly supports. This new lifting system can significantly reduce or even completely avoid contact fatigue damage at tubing thread connections, reduce the number of wells lying down due to tubing thread leakage, and lower the maintenance costs of mechanically operated wells. It also achieves continuous wellhead drainage and improved pump efficiency through deep pumping with small pumps.

The invention provides a method for measuring and calculating the abrasion loss of an involute gear based on a self-reference datum. The method does not need to depend on an external reference, measurement errors caused by reference deviation are effectively reduced, an accurate and rapid calculation method is found, accurate calculation of different involute gear abrasion losses can be achieved by changing the basic parameters of the gear, and the calculation accuracy is improved. Similarly, the abrasion loss of corresponding involute parts, such as involute splines, can be accurately calculated. And a key technical support is provided for wear loss precision control and data reliability of the gear tooth surface in gear wear and gear contact fatigue tests and process and parameter design of the gear.

This invention applies selective laser cladding (SLS) technology to the fabrication of reducer pin tooth housings, designing a lightweight, high-strength pin tooth housing with both material and structural gradients. In terms of materials, a gradient material layer-by-layer printing process is employed, with the outer layer using high-strength alloy steel as the base layer, the middle layer using GCr15 bearing steel powder, and the inner gear surface coated with a thin layer of AlCoCrFeNi high-entropy alloy powder. A certain proportion of transition zone material is incorporated between each layer to enhance the wear resistance and contact fatigue strength of the pin tooth housing. Structurally, a certain structural gradient is used, with a three-layer structure designed using UG 3D modeling software. The top and bottom layers are solid and gapless, while the middle layer uses a negative Poisson's ratio hollow structure, significantly reducing the weight of the pin tooth housing and achieving lightweight design. This dual-gradient design allows the reducer to maintain better overall mechanical performance while achieving a lightweight design.

The invention relates to the technical field of microstructure refinement and homogenization of bearing steel, and specifically relates to a high-carbon bearing steel and a method of preparing same. The high-carbon bearing steel of the invention has the following chemical composition: C: 0.80˜1.20 wt %, Cr: 0.40˜2.0 wt %, Mn: 0.15˜0.75 wt %, Si: 0.15˜0.75 wt %, Nb: 0˜0.20 wt %, Mo: 0˜0.20 wt %, V: 0˜0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities; the contents of Nb, Mo and V are not 0 at the same time. According to the invention, microalloying elements such as Nb, Mo and V, in combination with other elements, are added into the high-carbon bearing steel to effectively refine the bearing steel matrix and promote the precipitation of a large amount of nano-carbides, thereby enhancing the contact fatigue life of the high-carbon bearing steel.

The invention provides the application of the test method in testing the rolling contact fatigue performance of the steel rail material in a humid and / or corrosive environment. The invention also provides a test method for testing the rolling contact fatigue performance of the steel rail material, which comprises the following steps: preparing a steel rail test sample, simulating a humid and corrosive environment, and carrying out a double-wheel rolling contact fatigue test according to test requirements; and evaluating the contact fatigue performance of the sample through weightlessness, vibration signals and the surface state of the sample. The test mode better conforms to the actual service condition of the steel rail line in the humid and corrosive environment, and the test result is more accurate and effective. The steel rail material rolling contact fatigue test method provided by the invention can evaluate the contact fatigue performance of multi-steel-grade steel rails in a humid and corrosive environment, and parameters such as corrosive liquid and test pause interval time can be adjusted according to actual requirements. The method is suitable for test evaluation of various service conditions such as coastal, tunnel and plateau, and has a good application prospect.

This invention provides a high surface hardness gear steel for new energy vehicles, its production method, and heat treatment process. The composition is: C 0.25-0.30%, Si 0.25-0.45%, Mn 1.15-1.35%, P ≤0.015%, S ≤0.015%, Cr 1.11-1.27%, Mo 0.7-1.00%, Al 0.025-0.035%, Ti 0.03-0.05%, Ni 1.4-1.6%, Cu ≤0.2%, [N] 30-50ppm, TO ≤15ppm, [H] ≤1.5ppm, with the remainder being Fe and unavoidable impurity elements. After isothermal normalizing pretreatment + carburizing gas quenching + low-temperature tempering, the carburized layer grain size is ≥10.0 grade, and the surface hardness is ≥800HV. 10 ≥3.0×10 7 L 50 ≥6.5×10 7 This meets the requirements of new energy vehicles for high contact fatigue performance.

The invention discloses a forging device for metal processing and manufacturing and capable of improving contact fatigue strength of tooth surfaces, and relates to the technical field of metal forging and polishing. The forging and pressing device for metal machining and manufacturing and capable of improving the contact fatigue strength of the tooth surface comprises a box body, a supporting frame is arranged at the top of the rear side of the box body, and rotary driving equipment is movably connected into the box body; an electric push rod is fixedly connected to the top of the supporting frame, a hollow rod is fixedly connected to the bottom of the electric push rod, a reciprocating lead screw is movably connected to the interior of the hollow rod, a threaded sliding block is in threaded connection to the outer side of the reciprocating lead screw, and the outer side of the threaded sliding block is slidably connected with the hollow rod through a sliding groove; the outer side of the threaded sliding block is rotationally connected with a guide block through a first rotating shaft, and the first rotating shaft is movably connected with the guide block through a transmission piece. According to the forging and pressing device for metal machining and manufacturing and capable of improving the tooth surface contact fatigue strength, through vertical reciprocating motion and angle change of the guide block, parts are polished more completely, and the working efficiency of equipment is improved.

The application discloses a residual stress improvement method for a railway wheel, and specifically as follows: determining vibration parameters of a vibration aging treatment, including exciting force, exciting time and exciting frequency of different tread depths, and then performing the vibration aging treatment on the wheel. The residual stress improvement method based on the vibration aging treatment improves the production efficiency of the wheel, and compared with a wheel treated by a traditional quenching + tempering process, the wheel treated by the vibration aging treatment can effectively reduce the residual stress of the wheel, the shrinkage value of the wheel flame cutting is reduced by about 30%, and the mechanical properties and the contact fatigue properties can be improved.

The present application relates to line surface combined contact type wind power variable pitch slewing bearing, comprising: double half outer ring, inner ring, double row axial combined rolling unit and radial roller; The upper and lower cooperation of the double half outer ring forms a whole outer ring and is matched with the inner ring to form a bearing sleeve; The outer diameter center area of the inner ring is provided with a protruding structure extending to the inner diameter of the outer ring, the double half outer ring includes upper half outer ring and lower half outer ring, and the outer diameter protruding outer surface of the inner ring is provided with a groove structure; The upper and lower end faces of the protrusion form a space for bearing double row axial rolling unit between the inner diameter of the retaining edge of the double half outer ring, and the space for bearing radial roller is formed between the protruding groove and the corresponding inner diameter of the outer ring; The axial combined rolling unit comprises: 4 independent bodies and a plurality of cylindrical rollers; It has strong axial bearing capacity, and has strong advantages in axial adaptive inclination and anti-overturning capacity; Reduce the risk of traditional three-row cylindrical slewing bearing contact fatigue.

The present application belongs to the field of die steel heat treatment, and relates to a quenching heat treatment method for enhancing contact fatigue of die steel. The present application adopts a multi-stage heat treatment strategy, effectively improves the microstructure of the die steel, improves the uniformity and stability of the material, and maintains good toughness, and solves the problem of traditional heat treatment methods at the cost of sacrificing the internal uniformity of the material by cyclic operation of heating the die steel to phase transition temperature T1+(30-50 DEG C) and cooling to phase transition temperature T1-(30-50 DEG C).

The invention discloses a steel rail with excellent fatigue resistance and corrosion resistance and a manufacturing method thereof, and the manufacturing method comprises the following steps: S1, casting a first casting blank and a second casting blank, milling scale on the surface layer of an upper wide surface until the surface is flat, and then oppositely stacking the milled surfaces; s2, welding and sealing joints of the casting blank in a vacuum chamber through an electron beam welding machine to form a combined casting blank, and heating the combined casting blank until the combined casting blank is easy to deform; and S3, the steel rail is manufactured through cogging by a cogging mill, rough rolling by a universal rolling mill, medium rolling and finish rolling, the first casting blank is rolled into a steel rail head, the second casting blank is rolled into a rail web and a rail bottom, the steel rail head is accelerated to be cooled to 500 DEG C or below at a high cooling speed, and the rail bottom is accelerated to be cooled to the room temperature at a medium cooling speed. By adopting a railhead and rail bottom performance differential cooling strategy and a combined casting blank rolling steel rail technology, the contradiction that corrosion resistance, contact fatigue resistance, (low-temperature) toughness and plasticity, weldability and other performance are difficult to synergistically improve theoretically is solved, and the actual service performance of the steel rail is greatly improved.

The application relates to the technical field of mechanical engineering, and discloses a kind of angular contact ball bearing optimization design method, according to the load of rotor system and bearing installation structure space, the load of double half inner ring angular contact ball bearing is calculated, and the structure parameters of double half inner ring angular contact ball bearing are designed;The load actually borne by angular contact ball bearing under the working state of rotor is analyzed, the three-point contact, climbing, contact stress of rolling body and sleeve ring are calculated, the bearing structure parameters meeting the requirement of bearing steady-state performance are determined by adjustment;Then, through carrying out bearing dynamic performance analysis, according to bearing film thickness ratio and motion stability, the cage parameters or bearing roughness are optimized, so that the steady-state and transient performance of the bearing meet the design requirements.The application comprehensively considers the load transmission relationship between the bearing and the rotor, and on the basis of fully considering the change law of the dynamic performance of the bearing, such as contact fatigue, slip, three-point contact and cage motion stability, the structure parameters of the double half inner ring angular contact ball bearing are optimized.

A bearing high-temperature contact fatigue test device comprises a shell, a test bed is arranged in the middle of the shell and located at the top end of a supporting shaft, a thrust shaft is arranged below the supporting shaft, and a transmission shaft is arranged above the test bed. According to the high-temperature test device, the use requirements of equipment at the high temperature of 250 DEG C + / -5 DEG C, the load of 100-1000 kgf, the rotating speed of a main shaft of 0-2000 rpm and the adjustable speed are met, the real service state of the thrust piece in the high-temperature state is better simulated, more real test data are obtained on a testing machine, and a test basis is provided for high-temperature material selection of parts and improvement of material fatigue performance.

The invention discloses a production method for improving wear resistance of a pearlite steel rail. The specific production process comprises the following steps: (1) heating a steel billet; (2) rolling is conducted, specifically, the steel billet is rolled into a steel rail through a universal rolling mill, the initial rolling temperature is 1100 + / -30 DEG C, and the final rolling temperature is 925-940 DEG C; the cooling process of the steel rail is mainly divided into three stages; the pearlite rail steel comprises the following element components in percentage by mass: 0.78 to 0.80 percent of C, 0.61 to 0.71 percent of Si, 0.90 to 0.98 percent of Mn, 0.04 to 0.12 percent of V, less than or equal to 0.02 percent of P and less than or equal to 0.02 percent of S. And the balance of iron and inevitable impurities. Through the component optimization-gradient cooling-heat treatment process, on the premise that the toughness of a steel rail matrix is guaranteed, the hardness, wear resistance and contact fatigue resistance of a railhead key wear area are remarkably improved, and the service life of the steel rail is prolonged.

A method for determining the surface strengthening process of a rotating wheel is disclosed. This method involves conducting research on the surface strengthening of Cr12MoV material and utilizing QPQ technology to strengthen the surface of the rotating wheel. The strengthened rotating wheel is then applied to complex working conditions requiring high load, high wear resistance, and resistance to contact fatigue. The invention involves surface nitriding, nitrocarburizing, and composite QPQ salt bath treatment of the specimens. Based on the research results of the process parameters for these three surface strengthening methods (see Figures 3-5), the surface hardness and tribological properties of the specimens under different surface strengthening regimes are compared and analyzed. Analysis of the experimental data shows that the composite QPQ salt bath treatment exhibits the best wear resistance and meets the hardness requirements for the rotating wheel's operation. Therefore, composite QPQ salt bath treatment is determined as the method for strengthening the rotating wheel surface. Experimental verification shows that the service life of the rotating wheel strengthened by this invention is increased by 10% compared to the untreated rotating wheel.

The invention discloses a steel rail material for a subway small-radius curve line, and the rail head area of the cross section of a steel rail is divided into three areas according to different microsizes of pearlite structures, namely a surface regulation and control layer, a rail angle hardening area and a core base body area. Aiming at more small-radius curves of the subway line at present, the microstructure of different stressed parts of the steel rail head is reasonably designed and arranged on the basis of the wheel-rail contact relation and stress distribution characteristics of the small-radius curve line, so that the steel rail material rail head is ensured to have the wear and the surface contact fatigue crack cooperative control, and meanwhile, the steel rail material rail head is ensured to have a good anti-fatigue effect. And the generation and development of internal fatigue cracks can be reduced. Meanwhile, gradient distribution and stable control of pearlite structures of different parts of the rail head of the steel rail are achieved by controlling rolling and conducting accelerated cooling at different speeds on the rail head, and generation and development of steel rail abrasion and rolling contact fatigue damage on a small-radius curve line are effectively relieved; the comprehensive use performance and the service life of the steel rail are improved.

The application discloses a kind of fatigue testing devices of non-contact adjustable centrifugal load, belong to centrifugal testing technical field, it includes: test frame, it is set as L-shaped structure;Fixed frame is fixed on the test frame, two bearing seats are vertically distributed on the fixed frame;Main shaft, vertically through connection between two bearing seats;Centrifugal regulation unit is rotatably installed on the fixed frame, the upper end of the main shaft is connected with the centrifugal regulation unit;Belt driving device is installed on the test frame, and the lower end of the main shaft is connected with the transmission of belt driving device;Connecting shaft is fixed in the center of the upper end of the centrifugal regulation unit;The application can realize the non-contact continuous adjustment of centrifugal load using lever adjustment assembly, in addition, by changing the polarity of magnet on magnetic guide base, realize the intermittent adjustment between each centrifugal load in rotation of centrifugal regulation unit, enhance centrifugal effect, more truly simulate non-stationary excitation in actual working condition.

The invention discloses a metal processing and manufacturing forging device capable of improving tooth surface contact fatigue strength, and belongs to the technical field of metal forging, the metal processing and manufacturing forging device comprises a base, a forging table, a control frame and a hydraulic control module, a hydraulic rod is connected with the hydraulic control module through an oil guide pipe, and a forging head is arranged at the driving end of the hydraulic rod; at least two transverse hydraulic rods and forging dies connected with the telescopic ends of the transverse hydraulic rods are arranged at the top of the forging table, the forging dies are spliced to form an annular forming space which is used for limiting material extension during metal blank forging, and a plurality of fixed forming pieces and at least one movable forming piece are arranged on the inner side wall of each forging die. One end of the movable forming piece is connected with a hammering driving piece arranged at the top of the forging and pressing table; refining of metal grains and flowing of metal in gaps are effectively promoted, the tooth surface strength and abrasion resistance are effectively improved, and therefore the contact fatigue strength of the tooth surface is improved.

The application discloses a high-load roller bearing structure and material fatigue strength optimization and performance evaluation method, and relates to the technical field of bearing design and manufacturing. The method comprises the following steps: obtaining structure geometric parameters, heat treatment process parameters and chemical composition data of the bearing; calculating the hardening layer depth, surface hardness and residual stress distribution based on physical metallurgical rules; converting the microstructure features into the contact fatigue limit and stress correction factor; establishing a slice method contact mechanics model to solve the contact load distribution; taking the structure geometric parameters and heat treatment process parameters as double design variables, and taking the maximum fatigue life and the minimum heat treatment process cost as double objectives to construct a multi-objective optimization function; solving the Pareto optimal solution set by using a non-dominated sorting genetic algorithm; and evaluating the candidate schemes and generating an optimization report. The application solves the technical problem that the structure design and the heat treatment process are mutually separated and cannot be optimized in a cooperative manner in the prior art.

The invention provides a composite shot peening process parameter optimization method and system based on a spiral bevel gear contact fatigue life prediction model, and relates to the technical field of process parameter optimizing.The method comprises the specific steps that fatigue tests are conducted on spiral bevel gears manufactured through different composite shot peening process parameter combinations; parameters such as initiation fatigue life and extended fatigue life are obtained, a gear contact fatigue life prediction model is constructed on the basis, different composite shot blasting process parameter combinations serve as input, the parameters such as life and residual stress serve as a label training model, and the problem that prediction models are lacked in the prior art is solved; effective prediction of the fatigue life in actual use is achieved, then data processing and correlation analysis are conducted on the obtained parameters, a comprehensive evaluation coefficient is generated, the relation between each fatigue performance parameter and the fatigue life is quantified, the maximum comprehensive evaluation coefficient serves as the target, iterative optimization is conducted through a genetic algorithm, and the optimal value of the composite shot blasting process parameters is obtained. And the fatigue life of the spiral bevel gear is pointedly prolonged.

The application provides a bearing steel with good corrosion resistance and high strength and a production method and a heat treatment method thereof, and the composition is as follows: C 0.88%-1.00%, Si 0.40%-0.60%, Mn 0.3%-0.5%, Cr 1.5%-1.7%, Mo 0.1-0.25%, Nb 0.010%-0.025%, Ni 0.20%-0.30%, Ti<=0.0015%, Alt<=0.020%, P<=0.010%, S<=0.010%, T.O<=0.0015%, N<=0.0065%, and the rest is Fe and other inevitable impurities. Compared with the prior art, the application has good strength and plasticity and toughness of the product after heat treatment, and has excellent contact fatigue life and corrosion resistance through the composition and process design.

The present application belongs to the technical field of metal rolling production, and particularly relates to a rolling fatigue damage calculation method considering coupling of contact fatigue damage and wear. The method comprises the following steps: step one, constructing a continuous damage mechanics model of rolling material; step two, constructing a rolling contact fatigue damage calculation model; step three, calculating unit damage; step four, constructing a wear amount calculation model of rolling material; step five, determining a wear coefficient through "strength-hardness" correlation; step six, calculating unit wear; and step seven, iterative calculation: after rolling body discretization, initial parameter assignment and iterative parameter setting are sequentially performed, iterative calculation in each interval is carried out according to the divided rolling service time interval, and a complete rolling fatigue damage of coupling contact fatigue damage and wear in a complete in-service period is iteratively calculated. The method solves the problems of excessive model simplification and ignored coupling effect in the existing evaluation method, and improves the calculation accuracy of rolling damage distribution.

The invention provides a steel rail material rolling contact fatigue test method. A rolling contact fatigue test sample and a rolling accompanying grinding sample are machined on a steel rail head; carrying out laser engraving on the surface of the test sample to simulate a hurt in a required shape and depth; performing ultrasonic cleaning on the test sample and the grinding accompanying sample by using anhydrous B, drying, weighing and recording, performing a rolling contact fatigue test, and setting the test load, the rotating speed of the test sample and the grinding accompanying sample and the total test cycle according to test requirements; after the required test cycle is reached, stopping the test, recording a vibration signal, and taking down the test sample and the accompanying grinding sample; and ultrasonically cleaning the test sample by using anhydrous B, airing, weighing and recording. And subtracting the weight after the test from the weight of the test sample before the test to obtain the weight loss. The contact fatigue performance of multi-steel-grade steel rails under the condition that the multi-steel-grade steel rails are damaged can be evaluated, and the size, the shape and the depth of the engraved marks can be adjusted according to actual requirements; the method is suitable for test evaluation of various service conditions of high-speed, heavy-load and ordinary-speed railway steel rails and the like, and has a good application prospect.

This invention belongs to the field of metallurgical technology, specifically relating to a high fatigue life 20MnCr5NbH gear steel and its production method. The chemical composition of the gear steel billet by weight percentage is: C: 0.17%~0.22%, Si: 0.15%~0.35%, Mn: 1.10%~1.30%, Cr: 1.00%~1.25%, Nb: 0.020%~0.050%, N≤0.012%, with the balance being Fe and unavoidable impurities; the production method includes the following steps: (1) smelting and continuous casting to obtain a steel billet, (2) heating the continuously cast billet to 1220~1260℃ and holding it for ≥280min; (3) using two-stage controlled rolling; (4) water cooling after rolling. This invention, through the addition of trace amounts of Nb and process synergy, increases the gear contact fatigue limit to over 1700MPa and the bending fatigue limit to over 600MPa.

The invention belongs to the field of metal material surface strengthening, and relates to a surface wear resistance and rolling contact fatigue protection method of a metal transmission component, in particular to a method for prolonging the service life of a bearing by forming an oxide layer on the surface of the metal bearing. The method comprises the steps of metal surface grinding, polishing treatment, cleaning and drying. Lubricating oil containing additives is used; a dense micro-convex oxide layer is formed, and the oxide layer is composed of a metal oxide containing a large number of fine metal particles. The method can be carried out in the using process of the bearing, the cyclic contact stress damaging the surface of the bearing is converted into a method for strengthening the surface of the bearing, the rolling contact fatigue performance of the bearing is improved, the service life of the bearing is prolonged, and the method can be widely applied to various bearings.

Provided in the present invention is a fatigue criterion and data-driven integrated method for gear fatigue pitting life prediction. The method comprises: collecting gear contact fatigue data of different materials from published literature, so as to construct an original data set; on the basis of gear parameters and engagement conditions in the literature, using ABAQUS simulation software to establish a two-dimensional finite element model of a local spur gear; using precise stress and strain results obtained by means of simulation to perform life calculation and verification in combination with an FS method; calculating pitting life within an experimental contact stress range by means of changing loads and using the FS method, so as to expand the original data set; applying a generative adversarial network model to further expand the data set; and finally, on the basis of the recombined data set, establishing a graph convolutional network model to perform fatigue pitting life prediction. The present method exhibits higher accuracy in prediction results. The implementation of the method provides an effective solution for small-sample failure analysis of a gear transmission system, thereby demonstrating engineering application value.

Systems, methods, and computer program products for detecting damage to an object (186). A non-contact vibration sensor (161) is used to sense surface vibrations on a surface of the object (186). A waveform (32) is defined based on the surface vibration data (171), and one or more features (34) (38) (42) (44) are extracted from the waveform (32). The extracted features (34) (38) (42) (44) are analyzed to determine if damage has occurred to the object (186).

The application discloses a kind of oblique-tooth cylindrical gear time-varying reliability optimization design method and system, the method includes: the gear reliability optimization design model of minimum volume of gear body is established as optimization goal, and time-varying reliability in whole life cycle is constraint;Coupling time-varying load spectrum and material strength degradation model is constructed gear contact fatigue time-varying limit state function;Time-varying reliability analysis module based on proxy model and active learning strategy is constructed to evaluate time-varying limit state function;Optimization algorithm is used to solve the gear reliability optimization design model, the time-varying failure probability of candidate scheme is evaluated by calling the time-varying reliability analysis module and accordingly the time-varying reliability constraint is processed, and the optimal gear design parameter meeting the constraint is output.The application realizes the efficient cooperation of high-precision evaluation and lightweight optimization design of time-varying reliability, solves the problem that traditional method cannot consider time-varying factor in optimization due to high analysis cost.