For a typical fault of a type of aircraft landing gear, based on its working principle, the fault tree analysis method was used to analyze and diagnose the fault. A fault tree and fault structure function with the fault phenomenon as the top event were established, and all basic events corresponding to the fault were obtained.Combined with the prior probability of the basic event of such faults calculated by a certain company, the failure probability of the fault phenomenon was calculated through importance, and a fault diagnosis process was developed to provide a basis and reference for the efficient diagnosis, analysis, and maintenance of such faults in this type of aircraft.

Ball screw is a key transmission component in electro-hydraulic servo equipment, and its structural design will have a direct impact on the mechanical properties and further affect the stability and life of its transmission. The system was analyzed by ABAQUS solver to study the ball load carrying situation and the influence of nut structure on its load. The results show that the secondary development of ABAQUS based on Python can realize the whole process of finite element parametric modeling and static analysis of ballscrew sub-systems, which provides data and methods for the subsequent study of the optimization of the structural design of the nut returner and the selection of materials.

In order to improve the efficiency of automatic fruit picking, deeply implement the concept of technology strengthening agriculture and smart agriculture, taking tomato picking as an example, a two axis harvesting robotic arm is designed according to the functional requirements of tomato fruit picking process and the structural characteristics of human arms, using ANSYS Workbench software to optimize its structure. The end effector is designed as a flexible pneumatic driven robotic arm, building a robotic arm and simulating its motion posture in the RobotStudio, finally, the camera, a key component of the visual system of the tomato picking robot, is set up and programmed for control. The construction of an automatic recognition tomato picking robotic arm control system has been completed.

A detailed model for a rotationally balanced constant-pressure dual-row axial piston pump was meticulously developed, followed by an extensive AMESim simulation. This simulation investigated how outlet pressure impacts flow, the correlation between outlet pressure and the distribution plate's rotation angle, and the pump's dynamic behavior with sudden changes in the variable orifice signal. The analysis considered the nuanced effects of reset spring stiffness in the variable mechanism and valve stiffness in the pressure control valve. The findings highlighted a decrease in outlet flow with rising outlet pressure and an increased rotation angle of the distribution plate. A stiffer reset spring led to quicker dynamic response and reduced overshoot in the pump. Conversely, a larger valve core diameter slowed down the pump's dynamic response, prolonged steady-state attainment, and intensified flow and pressure oscillations by amplifying the distribution plate's rotation during that phase.

With the increasing emphasis on oxygen health care, the demand for oxygen machines for health care purposes has been growing year by year in the market, and the oxygen machine solenoid valve is a key component of medical health oxygen machines. The working principle of the oxygen machine and several main types of oxygen machine solenoid valves currently on the market are introduced, along with the performance characteristics of each oxygen machine solenoid valve.

This paper based on hydraulic landing gear test bed, combined hydraulic system, landing gear system, landing gear structure to carry out comprehensive test. Study on the working characteristics of an aircraft landing gear retraction system. Obtain the influence of hydraulic system output flow rate and switch control logic on the landing gear retraction and retraction characteristics. Meanwhile, the typical fault of landing gear down and hard unlocked during system test is analyzed. It is determined that the landing gear is hard unlocked due to back pressure on the lowering pipeline during the lift action when lowering the landing gear. Through the comparative analysis of theoretical research and experimental results, accurately locate the position where fault occurred, further deepen the understanding of the system.

Aiming at the crucial issues of serious friction and wear and large leakage in the key friction pair on the axial piston pump, the influence factors of pressure and shear flow are introduced, the oil film thickness equation considering the viscous-temperature effect was established, and the lubrication and leakage characteristics of the piston pair are analyzed using finite element method, and the following conclusions are obtained: When considering the viscous-temperature characteristics of the lubricant, the maximum oil film pressure is obviously greater than the film pressure without considering the viscous-temperature characteristics, and the minimum oil film thickness is much smaller than the minimum film thickness; with the increase of temperature, the oil film pressure gradually increases, and the film thickness gradually decreases. The leakage amount considering the viscous-temperature characteristics is obviously greater than the leakage amount without considering the viscous-temperature characteristics. When the temperature is greater than 60 ℃, the leakage rate increases significantly. With the increase of temperature, the leakage amount at different contact lengths increases nonlinearly. When the contact length is 17 mm, the leakage amount is the largest and the slope of the vary curve is the steepest, when the unilateral clearance increases above 3 μm, the leakage ratio increases significantly. The research can provide a reference for the accurate theoretical design of the piston pair and safe and stable operation of piston pumps.

Pneumatic valves are common pneumatic components that play a role in changing the direction of the airflow within the pneumatic system and are widely used in automated equipment, commercial vehicles, and medical devices. One important performance index of the pneumatic valve is flow rate. This paper takes a two position four-way solenoid valve as an example to carry out the design calculations for flow rate, structural calculations, flow simulation, and experimental verification, summarizing a general design process for the flow rate of pneumatic valves.

Focus on hydraulic pressure fluctuations in traditional accumulators during energy storage and release, a spring-based constant pressure accumulator is proposed. The operational principle of the accumulator is analyzed, with the profile curve equation for the critical component derived and solved. Key parameters for an accumulator in a specific hydraulic system are designed. A simulation model is constructed in ADAMS software to test the performance of the accumulator under varying flow conditions. It achieved a force deviation below 1% during stable operation, serving as a reference for the design of hydraulic energy storage systems.

The square hole filter is a typical pollution control component in aviation fuel systems, which is prone to blockage and other problems, seriously affecting the reliability of the filter and system. This article uses fluid simulation software to establish a simplified model of square hole filter screen. The CFD-DEM coupling method is used to study the filtration process of square hole filter screen components, and the influence of oil cleanliness and filter screen accuracy on filtration efficiency is analyzed. The results show that in the early stage of filter filtration, the main focus is on surface medium filtration, and the particle group smaller than the mesh size is the key to interception in the middle stage of filter filtration. The particle concentration and filter accuracy have a significant impact on the filtration efficiency of the filter. The higher the particle concentration, the lower the particle filtration efficiency; There are significant differences in the filtration efficiency of the same particles when passing through different specifications of filters. The smaller the filter size, the lower the filtration speed, the higher the filtration efficiency, and the more particles are intercepted. Under the condition of ensuring filtration performance, the accuracy of selecting filter specifications can be improved by one level.

In hydraulic fluid transmission systems, ISO 6149 inner cone sealing structure is widely used because of its good sealing effect, but this sealing structure has some shortcomings, such as cone hole is difficult to process, easy to cut the seal ring during installation, so a new sealing structure design method is proposed in this paper, through the comparison of ISO 6149 inner cone sealing structure, the sealing principle, characteristics and advantages of this type of sealing structure and method to determine the sealing parameters is given, the application is verified by practical application and simulation.

To investigate the impact of different valve core angles on the control characteristics of the high-pressure needle valve, a computational analysis was performed using Fluent software. The flow characteristics of the high-pressure needle valve were simulated at various degrees of valve opening. After model validation, an evaluation of the control capabilities of needle valves with different valve core angles was conducted, utilizing the inherent valve characteristics and the loss coefficient as assessment indicators. Subsequently, the analysis involved examining the variations in the flow field within the valve through the characteristics of pressure and velocity distributions. The study also investigated the areas within the high-pressure needle valve that are most susceptible to wear and tear. The results indicate that high-pressure needle valves with different valve core angles all exhibit quick-opening characteristics, which becomes more pronounced with increasing valve core angles. From 10% to 70% relative opening, the loss coefficient of the 8° valve core needle valve decreases from approximately 50% to around 6.8%, which indicates that the 8° valve core possesses greater pressure regulation capabilities in comparison to the 16° valve core. High-pressure nitrogen undergoes pressure fluctuations and creates high-speed zones at the valve core's throttling section. The throttling section near the outlet end is more prone to experiencing wear. The research results can provide valuable references for the optimization design of high-pressure needle valves and similar types of valves.

To select the appropriate materials for the butterfly plate and valve seat to ensure the strength and sealing performance of the triple-eccentric butterfly valve, the effects of three different materials on the strength and sealing performance of the triple-eccentric butterfly valve were studied by simulation. The results show that for GH4169, aluminum bronze and polytrifluorochloroethylene seats, the sealing pressure distribution of the triple eccentric butterfly valve is uneven, and there is a low sealing pressure area near the valve shaft. The suitable materials of the butterfly plate and seat can increase the sealing pressure in the low sealing pressure area, and improve the strength and sealing reliability of the three-eccentric butterfly valve. The sealing specific pressure ratio of the aluminum bronze seat is about 2 times of that of the GH4169 seat, which has good strength and sealing performance.

As a new type of volumetric pressure pump, spherical pump has the advantages of tiny volume, high power density, compact structure, and high reliability, which has strong potential against traditional hydraulic components in miniature hydraulic drive field. Currently, there is little research on spherical pumps, and there are problems such as incomplete theoretical foundations and modeling research, which to a certain extent hinder the full realization of the advantages of spherical pumps. Therefore, it is necessary to improve the theoretical and modeling foundation of spherical pump systems, and build a relatively universal kinematic analysis method for spherical pumps to provide theoretical support for the structural design optimization and promotion of spherical pumps. Based on the unique volume theory of spherical pumps, the structure and working principles of existing two configurations (A/B type) spherical pumps are analyzed, and mathematical motion models are established, which constructs the mapping relationship between kinematic characteristics and structural parameters. Then a comparative analysis is conducted between the A/B type, and through modeling and simulation, the accuracy of theoretical analysis is verified. By reversing the transmission chain, a new type of spherical pump with improved structure has been designed, which can reduce the number of precision spherical fits, improve processability, and achieve precise flow distribution in spherical pump.

This paper introduces the structure of dry gas seals and succinctly outlines their characteristics and working principles. with an emphasis on the basic structure of the dry gas seal control system, the selection of the dry gas seal control system, and the pre-treatment of gas and the regulation and control of gas. Additionally, the paper compiles and analyzes potential causes for abnormal instrument data within dry gas seal control systems, as well as the interplay between system malfunctions and seal failures. It also proposes experimental testing methods to address these issues. The findings and insights contribute to the design and maintenance of dry gas seal control systems in industrial applications, ensuring their effective operation and the stable performance of associated equipment. Moreover, the paper offers practical solutions that can be directly applied to on-site operation.

This article conducted experimental tests on the sealing performance, opening characteristics, and static characteristics of a prototype of a large flow plug-in hydraulic control one-way valve. By applying simulation technology, the flow field characteristics of the plug-in hydraulic control one-way valve port at different valve sleeve cone angles were calculated and analyzed, and the calculation results of the prototype model were compared and analyzed with the experimental test results. It is concluded that different valve sleeve cone angles have a significant impact on the flow field characteristics of the valve port of the plug-in hydraulic control one-way valve. Reasonable selection of valve sleeve cone angles can reduce pressure loss at the valve port, reduce the probability of valve port cavitation and noise generation, increase the stiffness of the valve, stabilize the flow state at the valve port, and improve the performance of the valve. This provides theoretical support for the design of the valve port structure of large flow plug-in hydraulic control one-way valves.

The state monitoring signal of the hydraulic system is affected by the characteristics of the circuit and the operating conditions of the pump unit, presenting complex and nonlinear characteristics, and the abnormal state is difficult to identify and diagnose accurately. This work proposes a diagnosis strategy for the abnormal state of the pump hydraulic system based on principal component analysis and random forest BP neural network to improve the diagnostic efficiency of equipment monitoring systems. Firstly, principal component analysis is performed based on state monitoring data to reduce data dimensions, while T² and SPE statistics are calculated for real-time anomaly detection of the process states. Secondly, a random forest BP neural network is used to predict and classify the abnormal samples. The experimental results show that the proposed method can effectively diagnose the leakage states of the system, detect a delay of 5 sample points, and achieve a prediction classification accuracy of 99.88%, which is an average improvement of 4.63% compared to existing methods.

The three-arm drilling jumbo is specialized equipment for hard rock tunnel construction using the drill-and-blast method. Its boom system is crucial for the extensive operational range of the end drill. Addressing the issues of easy vibration and large deformation in the boom system of the three-arm drilling jumbo, this paper proposes optimizing the mechanical structure strength and the first-order resonant frequency of the boom. It develops a high-stability electro-hydraulic drive system for the boom, enhancing the stability and reliability of the boom system of the three-arm drilling jumbo. Firstly, based on the analysis of the stress-strain distribution and modal characteristics of the traditional boom structure, this paper proposes an optimized design for the internal rib structure of the telescopic arm and the external rib structure of the main arm. Without affecting the overall structural dimensions, the maximum deformation of the main arm (with the telescopic arm fully extended) is reduced from 32.1 mm to 19.6 mm, and the first-order natural frequency of the main arm (with the telescopic arm fully extended) is increased from 2.36 Hz to 3.03 Hz. On this basis, a new high-stability electro-hydraulic drive system for the boom is developed. A simulation analysis model of the electro-hydraulic drive system is established, and parameters such as the spring stiffness of the balance valve, the flow area of the damping valve at the control port and oil return port of the balance valve, and the flow area of the damping valve in the main oil circuit are optimized to enhance the stability of the electro-hydraulic system. Through simulation modeling analysis, the influence laws of different hydraulic system parameters on the stability and dynamic characteristics of the boom control system are clarified. This paper proposes that the optimization of the boom's mechanical and hydraulic systems can improve the stability of the boom system, providing an important reference for the future design and debugging of three-arm drilling jumbos.

According to the actual engineering requirements that the internal installation space of the weapon launcher is limited, the impact speed of the recoil bar is fast, and it needs to run through the inside of the buffer, an improved new type of gradual hydraulic buffer structure is proposed. The dynamic modeling of the buffer is carried out based on the inclined plate gap flow theory and the oil compressibility theory. The model is solved by Simulink, and the changes of internal piston rod speed, stroke, oil pressure and buffer force are analyzed under different initial speed conditions. An ejection test scheme is designed, and the prototype is tested and verified by this scheme. the test results show that the maximum error of collision energy loss between theory and practice is 9.49%, the maximum error of buffer force is 9.69%, and the maximum error of buffer displacement is 4.67%. The applicability and accuracy of the theoretical model are verified. It provides a design theoretical basis for solving the smooth cushioning of the high-speed recoil bar in the limited space of the weapon launcher.

FluidSIM-H is a software package that combines hydraulic drive system design, teaching and simulation. The hydraulic circuit and electric control circuit of the power slide table of the combined machine tool are designed by using the features of the software CAD and simulation, according to the action sequence table of electromagnet and stroke valve of the hydraulic system of the power slide table of the combined machine tool, the actual simulation based on the circuit diagram of the physical model of the component is carried out through the parameter setting, it realizes the functions of fast advance, one working advance, two working advance, stay, fast retreat and in-situ stop of the power slide table of the combined machine tool. The practical application shows that the hydraulic system designed by the software meets the production demand and has obvious advantages of high feasibility and effectiveness.

To reduce the energy consumption of data centers and improve the air flow organization, as well as to solve the hotspot problem, loop type heat pipe backplate air conditioning is gradually being applied in data center renovation. This article tested the compressor-liquid power loop heat pipe backplate air condition system, combined with the concept of annual energy efficiency ratio in GB/T 19413—2010, measured the cooling capacity and total cooling power consumption at various operating points, calculated the annual energy efficiency ratio, and conducted comparative experiments with air-cooled compressor-liquid power loop heat pipe inter row air condition with the same cooling capacity. It can be seen that compressor-liquid power loop heat pipe backplate air conditioning has advantages under the condition of meeting the cooling load of the data center.

In order to conduct in-depth research on the safety and reliability of DN150 low-temperature shut-off valves during the testing process, a combination of numerical simulation analysis and on-site engineering experiments was used for the study. Using COMSOL Multiphysics software to calculate the heat dissipation, stress concentration, and fluid flow of a low-temperature shut-off valve in both open and closed states, the results show that there is a temperature gradient at the inner and outer shells of the valve, leading to significant temperature dissipation; Under the influence of thermal stress and fixed constraints, stress concentration occurs at the connection of corrugated pipe components; At the moment of valve opening and closing, the liquid nitrogen flow rate in the pipeline will experience a transient, and the fluid flow inside the valve will undergo vortex flow, affecting the sealing performance of the valve disc and seat sealing pair.

Taking the mechanical seal used in the ultra-low temperature liquid oxygen pump of a certain air separation unit as the research object, a simulation test system for ultra-low temperature mechanical seal was established. The simulation test was carried out using liquid nitrogen as the test medium, and the variation law of blowing nitrogen temperature and acoustic emission signal was studied. During the sealing start stop process, there was solid impact between the sealing end faces, and there was no solid impact during stable operation. The sealing end faces were in non-contact operation. During the start-up process, the fluid dynamic pressure effect between the sealing end faces is insufficient to form a complete fluid film, and there is micro convex contact. The acoustic emission signal rapidly increases and peaks appear. As the speed increases, the fluid dynamic pressure effect on the sealing end faces increases, and the acoustic emission signal gradually decreases until the sealing operation stabilizes and the acoustic emission signal tends to stabilize. During the shutdown process, as the rotational speed decreases, the shear effect of the fluid film decreases, and the acoustic emission signal first shows a slight decrease. Later, as the rotational speed continues to decrease, the fluid dynamic pressure effect is insufficient to form a complete fluid film, and the acoustic emission signal rapidly increases and peaks. The temperature of the nitrogen gas blown during the entire experiment was between 10.7 ℃ and 22.5 ℃, and the sealing design was reasonable, meeting the requirements for on-site use of the equipment.

The transient flow characteristics of an aviation micro plug-in relief valve are studied using CFD simulation technology. The research focuses on analyzing the fluid flow characteristics and spool motion characteristics during the valve opening process, including spool displacement, hydrodynamic forces, and transient pressure changes in the flow field. Dynamic grid technology is employed to divide the computational domain around the valve orifice with complex structure, considering grid migration and deformation caused by spool movement. Additionally, experimental studies are conducted to validate the accuracy of the simulation results at a product level. The experimental results show that the established CFD model exhibited good agreement with the start-up pressure-flow characteristic curves obtained from the tests, with a maximum error within 4.72%. Thus, the simulation model demonstrates a certain level of accuracy. The simulation results indicate that during the valve opening process, the researched relief valve has an opening pressure of approximately 26.1 MPa and a maximum flow rate of 22 L/min, displaying favorable flow and pressure characteristics. Furthermore, the valve exhibites rapid opening, minimal pressure fluctuations, and excellent opening performance. The stiffness of the spring has a certain influence on the opening performance, and the increase of stiffness will lead to the increase of the required opening pressure. Thus, it is necessary to strictly control this parameter in the machining process to ensure that the product meets the requirements of the opening performance.

Pneumatic shift system is used to reduce the driver's shifting force and improve the vehicle's shifting smoothness, which is an important link to improve vehicle safety. The existing pneumatic shift system has many problems, such as multiple pneumatic failures, poor man-machine coupling and low gear shift control precision. In the process of shifting, it is easy to have the shift stick and dislocation caused by man-machine confrontation, which leads to the shift failure and even leads to serious driving accidents. This paper analyzes the research status of pneumatic shift system fault diagnosis and pneumatic shift control system at home and abroad, and points out the existing problems and future development trends in the fault diagnosis ability of pneumatic shift system, compliance and flexible control of pneumatic shift system, which provides reference for the development of efficient pneumatic shift control system and real-time fault diagnosis technology.

The pump turbine of a pumped storage power station in China was used as a model for research, and according to its “S” characteristics, the movable guide vane airfoil was changed and assembled in the original water guide mechanism with different arrangement methods, and the influence of the change of the movable guide vane airfoil on the “S” characteristics of the pump turbine and the influence of the guide vane force characteristics were analyzed through numerical simulation based on the SST k-ω model. The results show that changing the airfoil of the guide vanes can effectively destroy the high-speed water ring between the active guide vanes and the impeller, reduce the obstruction of fluid flow into the impeller, and improve the flow state in the impeller area, and at the same time, the change of the movable guide vane airfoil also improves the radial force of the guide vane, and the peak-to-valley difference of the radial force becomes smaller after adding the modified movable guide vane, which has a good impact on the operation stability of the unit.

In order to further improve the overall efficiency of the emulsion pump, research has been conducted in the directions of the transmission system, hydraulic distribution system, and pressure control system for energy loss control measures. The study proposes a transmission method for the emulsion pump without a reduction mechanism and a processing technique for the inner bore of the slide based on meshed flat-top honing. Friction and wear tests are conducted to validate the wear reduction measures of the emulsion pump's crosshead-slide friction pair. The impact relationship between the high-pressure packing seal preload force and leakage is investigated, and experimental validation is performed to determine the preload force with the lowest energy loss. The original pressure control system is replaced with a variable frequency speed-regulated linkage unloading valve to reduce energy loss during the unloading process. The research findings are applied to a 630 L/min, 40 MPa emulsion pump, and industrial tests are conducted underground at the Bayan Obo coal mine. The overall efficiency is increased from the original 87% to 91.5%.

Based on the analysis of the GB/T 20081.1—2021 and GB/T 20081.2—2021, a set of electro-pneumatic control integrated test-bed which can be used for flow and pressure characteristics test of compressed air pressure regulators is set up. The flow-pressure characteristics(according to GB/T 20081.1—2021, the same below)and pressure regulation characteristics of conventional direct operated and pilot-type compressed air pressure regulators are tested, and the test data are analyzed after editing and processing to verify the feasibility of the method described in the current standards. it provides a reference for the test of flow and pressure characteristics of compressed air pressure regulators in the new national standard.

Aiming at the issue of lubricating property in the slipper pairs of axial piston pumps, micro textures are arranged on the surface of the sliding shoes textured surface slipper pairs of axial piston pumps, an orthogonal experimental scheme was adopted to simulate and study the effects of operating parameters (film thickness, speed), surface texture shape parameters (pit shape, diameter, depth to diameter ratio), and area ratio on the surface bearing capacity of the slipper pairs. The results showed that the primary and secondary order of the multiple influencing factors was speed, area ratio, pit shape, diameter, depth to diameter ratio, and film thickness. The optimal combination of multiple factors was speed 1500 r/min, area ratio 20%, spherical shape, diameter 500 μm, depth to diameter ratio 0.4, and film thickness 20 μm; Based on pressure and velocity cloud maps, the fluid dynamic lubrication effect of textured surfaces and the mechanism of improving surface bearing capacity were analyzed. On the basis of the optimal combination, the impact of single factor changes on bearing capacity was analyzed.

This article designs a bidirectional non elastic sealing group structure scheme for high temperature (200 ℃) and high pressure (150 MPa) working conditions. By reducing the dimension of the spring, an axisymmetric analysis model of the spring energy storage sealing group is established, and the influence of temperature and medium pressure on the sealing performance of the designed sealing group is analyzed. The results show that high temperature can reduce the peak contact pressure of the sealing jacket, but increase the contact width of the sealing jacket to compensate for the impact of material softening on sealing performance; High pressure will create extremely high peak pressure between the double lips of the sealing jacket, which is beneficial for achieving sealing.

Offshore wind power installation platform as one of the important platforms for the development of marine wind energy resources, offshore wind power installation platform lifting system is a key component of the wind power installation platform, which directly affects the working efficiency of the whole platform and platform safety. Based on the hydraulic lifting system of a 5600 t offshore wind power installation platform, a simulation model is established for the hydraulic system and the synchronous controller respectively, and Simulink/AMESim two simulation software are used to carry out a joint simulation to study the synchronous control effect after adding electro-hydraulic proportional valves on the basis of the original system. The PID controller and fuzzy PID controller are designed respectively to synchronise the four groups of hydraulic cylinders of the hydraulic lifting system, and the synchronous control effect of the two controllers on the hydraulic lifting system is compared and studied. Through the joint simulation results, compared with the original system set value of 1 m, the displacement synchronisation error of the conventional PID controller is reduced by 10.3 cm, and the fuzzy PID controller is reduced by 12.1 cm. when the set value is 2.15 m, the displacement synchronisation error of the conventional PID controller is reduced by 21.4 cm, and the fuzzy PID controller is reduced by 26.1 cm. The simulation test proves that the fuzzy PID controller has more excellent control performance, and can significantly reduce the displacement synchronisation error of the four groups of hydraulic cylinders in the lifting process of the hydraulic lifting system.

In the hydraulic control system of blast furnace mud gun, a large amount of oil supply is required in a short period of time when the rotating oil cylinder and mud pump work, which requires the use of large flow and high-power hydraulic pumps to match them. In addition, high-power electric motors are required, the volume of the oil tank is increased, and the space of the hydraulic station is increased, resulting in increased production costs. In order to solve this problem, an accumulator station has been developed to store the energy of hydraulic oil and quickly release it when needed, enabling the actuator to achieve fast and smooth movement. At the same time, the piston accumulator itself can be used as a gas booster cylinder to charge nitrogen gas to the storage tank. Relieving hydraulic system impact, achieving energy transfer between two incompatible liquids and gases, and improving the efficiency of the blast furnace mud gun hydraulic system.

The mining technology in China's coal industry is constantly upgrading, and the development of large mining height hydraulic supports is also rapidly increasing. The requirements for the strength characteristics of hydraulic supports to resist impact ground pressure have significantly increased. The safety valve is a key component of hydraulic support to resist impact and plays a role in overload protection. Therefore, analyzing the dynamic characteristics of safety valves is crucial for ensuring safe coal mining. In response to the problem of slow response speed in existing pilot operated safety valves, this paper proposes a dual variable throttling port controlled pilot safety valve using the A-type hydraulic half bridge principle. Based on its structure and working principle, a hydraulic support unloading circuit model with the safety valve was built in AMESim software. Simulation results showed that the pressure rise time of the safety valve was 2 ms, the steady-state overflow pressure was 49 MPa, the pressure overshoot rate was 29.5%, the flow rate was 1172 L/min, and the unloading time was 19 ms. In the hydraulic support unloading circuit model, the influence of adjusting the height of the hydraulic support column extension and the dynamic load impact force on the unloading characteristics of the safety valve is further analyzed.

During the vehicle turning process, there are issues of low stability and safety. Therefore, a method for active rear wheel steering of automobiles based on self disturbance rejection hydraulic control technology is proposed. By constructing a vehicle lateral dynamics model and designing a variable hydraulic transmission ratio algorithm based on it, the expected yaw rate of rear wheel steering can be accurately calculated; Using the expected yaw rate as the tracking target, design an active disturbance rejection hydraulic controller that includes an extended state observer, tracking differentiator, and nonlinear error hydraulic control law; By obtaining additional rear wheel steering angles and adjusting them, ensure that the car can closely follow the ideal model and achieve precise control of rear wheel steering. The simulation results show that by tracking the vehicle's center of mass sideslip angle and yaw rate, and applying hydraulic transmission ratio, the vehicle's stability is significantly improved, effectively preventing the risk of rollover and ensuring driving safety. At the same time, this control method enables the vehicle to exhibit excellent yaw rate response characteristics, and the estimated value of the center of mass lateral deviation angle is highly accurate, which is of great significance for improving the vehicle's steering performance and driving safety.

At present, the assembly of the servo mechanism supporting the joint bearing is mainly completed by manual press, which needs to test the proficiency of the operator, and increase dependence on the operator. The assembly efficiency is low, and the assembly quality consistency cannot be guaranteed. In order to improve the production efficiency and automatic production degree of workshop, in this paper, a bearing pressing method with automatic loading and unloading is proposed. By relying on the bearing pressing equipment with automatic loading and unloading of the bearing, the traditional assembly method relying on the press is optimized. Firstly, the whole structure is designed, and the working principle is introduced. Secondly, the key links are studied and the key parts are checked. Finally, the pneumatic circuit and the electrical control part of the equipment are introduced. In this paper, the technology method is proposed, which is of great significance to improve the production efficiency of workshop bearing assembly and improve the consistency of product quality.

The C-shaped sealing ring is the core component that ensures the sealing of the pressure vessel in nuclear power plants, and its sealing performance is directly related to the safe and stable operation of nuclear power plants. At present, the commonly used C-shaped ring in nuclear power plants is a sealed layer coated with silver. However, the usage temperature of the silver coated C-shaped ring is generally limited to below 400 ℃. For a new type of high-temperature nuclear power unit reactor pressure vessel with a design temperature of up to 550 ℃ and multiple cold and hot temperature cycling conditions, this paper introduces the main structural materials, manufacturing process, and technical key of a new type of nickel coated C-shaped ring, and conducts various cold and hot comprehensive performance tests on the new nickel coated C-shaped sealed sample ring at room temperature and high temperature. The experimental results show that the leakage rate of the new nickel coated high-temperature C-shaped sealing ring studied can reach ≤5.0×10^-6 Pa·m³/s at a high temperature of 550 ℃, which can be used for the engineering application of metal static sealing rings at 550 ℃ in nuclear power plants and other engineering fields.

A reverse parameterization design method for torque converter blades based on weak coupling bezier curves is proposed to address the issue of a certain existing hydraulic torque converter having a small energy capacity that cannot meet the matching requirements of high torque engines. By non-contact 3D scanning, the blade model and the silicone model of the flow channel are scanned and surface fitted to extract the point set matrix of the blade suction surface, pressure surface, and the intersection profile of the circulation circle. The two-dimensional expansion is carried out according to the contour preserving mapping of equal arc length. Then, two segments of cubic Bezier curves are used, and weak coupling is carried out through tangent horizontal constraints to reverse design the reverse two-dimensional profile. Based on reverse parameterization design, the stator is optimized by adjusting the key parameters of the stator blade bone line. CFD simulation and experiments show that, while the torque ratio remains basically unchanged and the maximum efficiency slightly decreases, the stall nominal torque has increased from 650.7 N·m to 773.2 N·m, with an increase of 18.83%. Satisfied the matching requirements of high torque engines. This method provides a new approach for parameterized reverse design and optimization design of hydraulic torque converters.

In the semi-outboard hydraulic system, compensating the return oil pressure is an important method to reduce the seawater infiltration into the system and improve its reliability. In this paper, a new type of oil return pressure compensator for deep-sea semi-outboard hydraulic system is presented, and its working principle is described. Through the analysis and mathematical modeling of its working process, the structural parameter design of each key part is introduced in detail. The test results show that the deep-sea adaptive pressure compensator can realize continuous pressure compensation under different states of the hydraulic system, and the maintenance pressure is always greater than the external marine environment pressure.

Different from Chinese conventional M310 unit, AP1000 unit reactor pressure vessel is an integrated top cover design structure, and its main bolt hole inspection must be checked on the integrated top cover flange surface, so this paper conducts inspection equipment positioning walking analysis and research, and design a pneumatic control system. Verified through experiments, the two dimensional measurement accuracy of inspection equipment is higher than 0.1 mm, the depth deviation during its walking positioning process is less than 1 mm. So that the inspection equipment can automatically walk along the arc on the top cover flange surface, and realize the precise positioning of the main bolt hole.