A complete mathematical model for logarithmic spiral type sprag one-way clutch design and analysis is given.It assumes that the motion of all clutch components can be expressed by a model of epicyclic gearing.It takes...A complete mathematical model for logarithmic spiral type sprag one-way clutch design and analysis is given.It assumes that the motion of all clutch components can be expressed by a model of epicyclic gearing.It takes advantage of Hunt-Crossley contact impact theory to calculate the contact forces between sprags and races,and it can be used for optimization of design and comparison with other types of sprag clutches.A good deal of analysis shows that the parameters of the steady windup angle,the steady contact force,the natural frequency and natural cycle of clutch have nothing to do with the initial velocity of outer race,while the parameters of the maximum transient windup angle,the maximum transient impact force and the steady engagement time increase linearly in the mode of engaging operation of clutch.It is also shown that the strut angle has great influence on the dynamic engagement performance of clutch.The parameters of the steady windup angle,the maximum transient windup angle,the steady engaging time,the steady contact force,the maximum transient impact force and the natural cycle of clutch decrease linearly nearly with the inner strut angle,while the natural frequency of the system increases linearly with the inner strut angle.展开更多
The effect of the design parameter on the clutch engagement process of the hydro-mechanical continuously variable transmission(CVT)was investigated.First,the model of the power train was developed with the software of...The effect of the design parameter on the clutch engagement process of the hydro-mechanical continuously variable transmission(CVT)was investigated.First,the model of the power train was developed with the software of SimulationX,and the clutch shift experiment was used to validate the correctness of the model.Then,the friction coefficient function was fitted with the test data to get the friction coefficient model suitable for this paper.Finally,based on the evaluating index of the friction torque and the friction power,two groups of design parameters(oil pressure and friction coefficient)were simulated and explained the changing regulation theoretically.According to the simulation results,the high oil pressure and friction coefficient can reduce the slipping time.The large oil pressure can increase the peak torque but the effect of friction coefficient on the peak torque is not so significant.The friction power reaches the maximum value at 3.2 s,the peak value increases as the oil pressure and friction coefficient increase.The effect of the oil pressure on the clutch engagement and thermal performance is greater than the friction coefficient.展开更多
For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Ai...For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Aiming at four different shift types,the ideal characteristics of shift clutch and engine control were set up.By using torque estimation method,PI slip control algorithm and engine coordinated control principle,the control model and transmission controller were well developed for three shift phases which included rapid-fill phase,torque phase and inertia phase.The testing environment on the rig and prototype vehicle level was built and the testing results obtained in ultimate condition could verify the accuracy and feasibility of this shift control strategy.The peak jerk during shift process was controlled within ±2 g/s where the smooth gearshift was obtained.The development proposal and algorithm have a high value for engineering application.展开更多
Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal...Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal and further analyzing the impact frequency. The signal local singularities under the wavelet transform are studied. According to the propagation features of modulus maximums of the fault signal and the noise under the wavelet transfor m different on the scales, and by use of the signal wavelet decomposition-recon struction algorithm, the clutch shell vibration acceleration signal is decompose d, denoised, and reconstructed.The signal-to-noise of the monitored signal imp roved greatly.The fault characteristic signal on time domain is positioned.The f ault characteristic frequency is picked up. Experiment shows that it is quite effective.展开更多
基金Project(2011CB706800)supported by the National Basic Research Program of China
文摘A complete mathematical model for logarithmic spiral type sprag one-way clutch design and analysis is given.It assumes that the motion of all clutch components can be expressed by a model of epicyclic gearing.It takes advantage of Hunt-Crossley contact impact theory to calculate the contact forces between sprags and races,and it can be used for optimization of design and comparison with other types of sprag clutches.A good deal of analysis shows that the parameters of the steady windup angle,the steady contact force,the natural frequency and natural cycle of clutch have nothing to do with the initial velocity of outer race,while the parameters of the maximum transient windup angle,the maximum transient impact force and the steady engagement time increase linearly in the mode of engaging operation of clutch.It is also shown that the strut angle has great influence on the dynamic engagement performance of clutch.The parameters of the steady windup angle,the maximum transient windup angle,the steady engaging time,the steady contact force,the maximum transient impact force and the natural cycle of clutch decrease linearly nearly with the inner strut angle,while the natural frequency of the system increases linearly with the inner strut angle.
基金Project(CX(19)3081)supported by the Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province,ChinaProject(BE2018127)supported by the Key Research and Development Program of Jiangsu Province,China。
文摘The effect of the design parameter on the clutch engagement process of the hydro-mechanical continuously variable transmission(CVT)was investigated.First,the model of the power train was developed with the software of SimulationX,and the clutch shift experiment was used to validate the correctness of the model.Then,the friction coefficient function was fitted with the test data to get the friction coefficient model suitable for this paper.Finally,based on the evaluating index of the friction torque and the friction power,two groups of design parameters(oil pressure and friction coefficient)were simulated and explained the changing regulation theoretically.According to the simulation results,the high oil pressure and friction coefficient can reduce the slipping time.The large oil pressure can increase the peak torque but the effect of friction coefficient on the peak torque is not so significant.The friction power reaches the maximum value at 3.2 s,the peak value increases as the oil pressure and friction coefficient increase.The effect of the oil pressure on the clutch engagement and thermal performance is greater than the friction coefficient.
基金Project(51105017) supported by the National Natural Science Foundation of ChinaProject(2011BAG09B00) supported by the National Science and Technology Support Program of ChinaProject(2010DFB80020) supported by the Technology Major Project of the Ministry of Science and Technology of China
文摘For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Aiming at four different shift types,the ideal characteristics of shift clutch and engine control were set up.By using torque estimation method,PI slip control algorithm and engine coordinated control principle,the control model and transmission controller were well developed for three shift phases which included rapid-fill phase,torque phase and inertia phase.The testing environment on the rig and prototype vehicle level was built and the testing results obtained in ultimate condition could verify the accuracy and feasibility of this shift control strategy.The peak jerk during shift process was controlled within ±2 g/s where the smooth gearshift was obtained.The development proposal and algorithm have a high value for engineering application.
文摘Fault diagnose of the roller overrunning clutch is a headache problem in engineering at home and abroad. This paper introduces a new method to solve the problem by using the wavelet transform to separate fault si gnal and further analyzing the impact frequency. The signal local singularities under the wavelet transform are studied. According to the propagation features of modulus maximums of the fault signal and the noise under the wavelet transfor m different on the scales, and by use of the signal wavelet decomposition-recon struction algorithm, the clutch shell vibration acceleration signal is decompose d, denoised, and reconstructed.The signal-to-noise of the monitored signal imp roved greatly.The fault characteristic signal on time domain is positioned.The f ault characteristic frequency is picked up. Experiment shows that it is quite effective.
