Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Fir...Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Firstly, the experiment for wear mechanism verification proved that adhesive wear and abrasive wear did coexist during the working process of spool valves. Secondly coupling behavior of each wear mechanism was characterized by analyzing actual time-variation of model parameters during wear evolution process. Meanwhile, Archard model and three-body abrasive wear model were utilized for adhesive wear and abrasive wear, respectively. Furthermore, their coupling wear model was established by calculating the actual wear volume. Finally, from the result of formal test, all the required parameters for our model were obtained. The relative error between model prediction and data of pre-test was also presented to verify the accuracy of model, which demonstrated that our model was useful for providing accurate prediction of spool valve's wear life. (C) 2016 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.展开更多
The finite element method (FEM) and particle image velocimetry (PIV) technique are utilized to get the flow field along the inlet passage, the chamber, the metering port and the outlet passage of spool valve at th...The finite element method (FEM) and particle image velocimetry (PIV) technique are utilized to get the flow field along the inlet passage, the chamber, the metering port and the outlet passage of spool valve at three different valve openings. For FEM numerical simulation, the stream function ψ-vorticity ω forms of continuity and Navier-Stokes equations are employed and FEM is applied to discrete the equations. Homemade simulation codes are executed to compute the values of stream function and vorticity at each node in the flow domain, then according to the correlation between stream function and velocity components, the velocity vectors of the whole field are calculated. For PIV experiment, pulse Nd: YAG laser is exploited to generate laser beam, cylindrical and spherical lenses are combined each other to produce 1.0 mm thickness laser sheet to illuminate the object plane, Polystyrene spherical particle with diameter of 30-50 μm is seeded in the fluid as a tracing particles, Kodak ES 1.0 CCD camera is employed to capture the images of interested, the images are processed with fast Fourier transform (FFT) cross-correlation algorithm and the processing results is displayed. Both results of numerical simulation and PIV experimental show that there are three main areas in the spool valve where vortex is formed. Numerical results also indicate that the valve opening have some effects on the flow structure of the valve. The investigation is helpful for qualitatively analyzing the energy loss, noise generating, steady state flow forces and even designing the geometry structure and flow passage.展开更多
To increase the efficiency and reliability of the thermodynamics analysis of the spool valve, the precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke and thermal-...To increase the efficiency and reliability of the thermodynamics analysis of the spool valve, the precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke and thermal-hydraulic bond graph based on the conservation of mass and energy were introduced. Subsequently, the connection rule for the bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing the spool valve, the lumped parameter for mathematical model of the system was given. At last, the reliability of the mathematical model of the flow area and the thermal-hydraulic system for the sloping U-shape notch orifice on the spool were demonstrated by the test. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method.展开更多
In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonabl...In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonable method to optimize system dynamic performance.Integrating these two technologies into one component can combine their advantages together.However,few works focused on it.In this paper,a twin spools valve with switching technologycontrolled pilot stage(TSVSP)is presented,which applied DHT into its pilot stage while appending IMC into its main stage.Based on this prototype valve,a series of numerical and experiment analysis of its IMC performance with both simulated load and excavator boom cylinder are carried out.Results showed fast and robust performance of pressure and flow compound control with acceptable fluctuation phenomenon caused by switching technology.Rising time of flow response in excavator cylinder can be controlled within 200 ms,meanwhile,the recovery time of rod chamber pressure under suddenly changed condition is optimized within 250 ms.IMC system based on TSVSP can improve both dynamic performance and robust characteristics of the target actuator so it is practical in valve-cylinder system and can be applied in mobile machineries.展开更多
Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived.The computational fluid dynamics was used to analyze the flow features of the sloping U-shape notc...Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived.The computational fluid dynamics was used to analyze the flow features of the sloping U-shape notch on the spool,such as mass flow rates,flow coefficients,efflux angles and steady state flow forces under different operating conditions.At last,the reliability of the mathematical model of the flow area for the sloping U-shape notch orifice on the spool was demonstrated by the comparison between the orifice area curve derived and the corresponding experimental data provided by the test.It is presented that the bottom arc of sloping U-shape notch(ABU) should not be omitted when it is required to accurately calculate the orifice area of ABU.Although the theoretical flow area of plain bottom sloping U-shape notch(PBU) is larger than that of ABU at the same opening,the simulated mass flow and experimental flow area of ABU are both larger than these of PBU at the same opening,while the simulated flow force of PBU is larger than that of ABU at the same opening.Therefore,it should be prior to adapt the ABU when designing the spool with proportional character.展开更多
High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate a...High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously.A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system.A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design.Mathematical models of the opening process and flow rate of the valve are established.Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response.Corresponding formulas to solve 4 parts of the response time are derived.Key factors that influence the opening response time are analyzed.According to the mathematical model of the valve,a simulation of the opening process is carried out by MATLAB.Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve.Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool.The experimental results are in agreement with the simulated results,therefore the validity of the theoretical analysis is verified.Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa.The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s.According to the result of the load driving test,the valve can meet the demands of the driving system.The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.展开更多
Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability ...Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability typically associated with these valves,here,the beneficial effects of a triangular groove structure on the related hydraulic response are studied.A mathematical model of the pressure compensation system based on the power-bond graph method is introduced,and the AMESim software is used to simulate its response.The results show that the triangular groove structure increases the jet angle and effectively compensates for the hydrodynamic force.The steady-state differential pressure at the valve port of the new pressure compensation structure was 0.65 MPa.Furthermore,experimental results show that the pressure difference at the main valve port is 0.73 MPa,and that the response time is less than 0.2 s.It is concluded that the new compensation structure has good pressure compensation response characteristics.展开更多
The 2D digital simplified flow valve is composed of a pilot-operated valvedesigned with both rotary and linear motions of a single spool, and a stepper motor under continualcontrol. How the structural parameters affec...The 2D digital simplified flow valve is composed of a pilot-operated valvedesigned with both rotary and linear motions of a single spool, and a stepper motor under continualcontrol. How the structural parameters affect the static and dynamic characteristics of the valve isfirst clarified and a criterion for stability is presented. Experiments are designed to test theperformance of the valve. It is necessary to establish a balance between the static and dynamiccharacteristics in deciding the structural parameters. Nevertheless, it is possible to maintain thedynamic response at a fairly high level, while keeping the leakage of the pilot stage at anacceptable level. One of the features of the digital valve is stage control. In stage control thenonlinearities, such as electromagnetic saturation and hysteresis, are greatly reduced. To a largeextent the dynamic response of the valve is decided by the executing cycle of the control algorithm.展开更多
文摘Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Firstly, the experiment for wear mechanism verification proved that adhesive wear and abrasive wear did coexist during the working process of spool valves. Secondly coupling behavior of each wear mechanism was characterized by analyzing actual time-variation of model parameters during wear evolution process. Meanwhile, Archard model and three-body abrasive wear model were utilized for adhesive wear and abrasive wear, respectively. Furthermore, their coupling wear model was established by calculating the actual wear volume. Finally, from the result of formal test, all the required parameters for our model were obtained. The relative error between model prediction and data of pre-test was also presented to verify the accuracy of model, which demonstrated that our model was useful for providing accurate prediction of spool valve's wear life. (C) 2016 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.
文摘The finite element method (FEM) and particle image velocimetry (PIV) technique are utilized to get the flow field along the inlet passage, the chamber, the metering port and the outlet passage of spool valve at three different valve openings. For FEM numerical simulation, the stream function ψ-vorticity ω forms of continuity and Navier-Stokes equations are employed and FEM is applied to discrete the equations. Homemade simulation codes are executed to compute the values of stream function and vorticity at each node in the flow domain, then according to the correlation between stream function and velocity components, the velocity vectors of the whole field are calculated. For PIV experiment, pulse Nd: YAG laser is exploited to generate laser beam, cylindrical and spherical lenses are combined each other to produce 1.0 mm thickness laser sheet to illuminate the object plane, Polystyrene spherical particle with diameter of 30-50 μm is seeded in the fluid as a tracing particles, Kodak ES 1.0 CCD camera is employed to capture the images of interested, the images are processed with fast Fourier transform (FFT) cross-correlation algorithm and the processing results is displayed. Both results of numerical simulation and PIV experimental show that there are three main areas in the spool valve where vortex is formed. Numerical results also indicate that the valve opening have some effects on the flow structure of the valve. The investigation is helpful for qualitatively analyzing the energy loss, noise generating, steady state flow forces and even designing the geometry structure and flow passage.
基金Project(51175518)supported by the National Natural Science Foundation of China
文摘To increase the efficiency and reliability of the thermodynamics analysis of the spool valve, the precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke and thermal-hydraulic bond graph based on the conservation of mass and energy were introduced. Subsequently, the connection rule for the bond graph elements and the method to construct the complete thermal-hydraulic system model were proposed. On the basis of heat transfer analysis of a typical hydraulic circuit containing the spool valve, the lumped parameter for mathematical model of the system was given. At last, the reliability of the mathematical model of the flow area and the thermal-hydraulic system for the sloping U-shape notch orifice on the spool were demonstrated by the test. The good agreement between the simulation results and experimental data demonstrates the validity of the modeling method.
基金Supported by National Natural Science Foundation of China(Grant Nos.52005441,51890885)open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems(Grant No.GZKF-201906)+1 种基金Zhejiang Province Natural Science Foundation of China(Grant No.LQ21E050017)China Postdoctoral Science Foundation(Grant Nos.2021M692777,2021T140594).
文摘In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonable method to optimize system dynamic performance.Integrating these two technologies into one component can combine their advantages together.However,few works focused on it.In this paper,a twin spools valve with switching technologycontrolled pilot stage(TSVSP)is presented,which applied DHT into its pilot stage while appending IMC into its main stage.Based on this prototype valve,a series of numerical and experiment analysis of its IMC performance with both simulated load and excavator boom cylinder are carried out.Results showed fast and robust performance of pressure and flow compound control with acceptable fluctuation phenomenon caused by switching technology.Rising time of flow response in excavator cylinder can be controlled within 200 ms,meanwhile,the recovery time of rod chamber pressure under suddenly changed condition is optimized within 250 ms.IMC system based on TSVSP can improve both dynamic performance and robust characteristics of the target actuator so it is practical in valve-cylinder system and can be applied in mobile machineries.
基金Project(51004085)supported by the National Natural Science Foundation of China
文摘Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived.The computational fluid dynamics was used to analyze the flow features of the sloping U-shape notch on the spool,such as mass flow rates,flow coefficients,efflux angles and steady state flow forces under different operating conditions.At last,the reliability of the mathematical model of the flow area for the sloping U-shape notch orifice on the spool was demonstrated by the comparison between the orifice area curve derived and the corresponding experimental data provided by the test.It is presented that the bottom arc of sloping U-shape notch(ABU) should not be omitted when it is required to accurately calculate the orifice area of ABU.Although the theoretical flow area of plain bottom sloping U-shape notch(PBU) is larger than that of ABU at the same opening,the simulated mass flow and experimental flow area of ABU are both larger than these of PBU at the same opening,while the simulated flow force of PBU is larger than that of ABU at the same opening.Therefore,it should be prior to adapt the ABU when designing the spool with proportional character.
文摘High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously.A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system.A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design.Mathematical models of the opening process and flow rate of the valve are established.Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response.Corresponding formulas to solve 4 parts of the response time are derived.Key factors that influence the opening response time are analyzed.According to the mathematical model of the valve,a simulation of the opening process is carried out by MATLAB.Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve.Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool.The experimental results are in agreement with the simulated results,therefore the validity of the theoretical analysis is verified.Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa.The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s.According to the result of the load driving test,the valve can meet the demands of the driving system.The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.
基金This research was funded by the 2020 Shandong Province Key Research and Development Programs(Major Technological Innovation Projects):Construction Machinery Integration Research and Application of Key Technologies for Intelligent Integration and Matching of Vehicle Assembly(2020CXGC011005)Large Tractor Hydraulic CVT Intelligent Continuously Variable Transmission Integration Research and Application(2020CXGC010806)Development and Application of High-Horsepower High-Efficiency Intelligent Tractors(2021CXGC010812).
文摘Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability typically associated with these valves,here,the beneficial effects of a triangular groove structure on the related hydraulic response are studied.A mathematical model of the pressure compensation system based on the power-bond graph method is introduced,and the AMESim software is used to simulate its response.The results show that the triangular groove structure increases the jet angle and effectively compensates for the hydrodynamic force.The steady-state differential pressure at the valve port of the new pressure compensation structure was 0.65 MPa.Furthermore,experimental results show that the pressure difference at the main valve port is 0.73 MPa,and that the response time is less than 0.2 s.It is concluded that the new compensation structure has good pressure compensation response characteristics.
基金This project is supported by National Natural Science Foundation of China (No.50075082).
文摘The 2D digital simplified flow valve is composed of a pilot-operated valvedesigned with both rotary and linear motions of a single spool, and a stepper motor under continualcontrol. How the structural parameters affect the static and dynamic characteristics of the valve isfirst clarified and a criterion for stability is presented. Experiments are designed to test theperformance of the valve. It is necessary to establish a balance between the static and dynamiccharacteristics in deciding the structural parameters. Nevertheless, it is possible to maintain thedynamic response at a fairly high level, while keeping the leakage of the pilot stage at anacceptable level. One of the features of the digital valve is stage control. In stage control thenonlinearities, such as electromagnetic saturation and hysteresis, are greatly reduced. To a largeextent the dynamic response of the valve is decided by the executing cycle of the control algorithm.