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The dynamic cushioning properties of locking clutch for a hydrodynamic transmission vehicle are studied to improve the locking quality in the transition process from hydrodynamic transmission operating condition to mechanical condition, in particular, to reduce the impact in vehicle’s locking process.The dynamic models for hydrodynamic torque converter with locking function and its input and output components are established. And the effects of oil-filling, buffer boosting, and step boosting on the locking quality during locking are analyzed. The optimal Latin hypercube design method is used to optimize the buffer slope in the buffer boost stage. The quality evaluation parameters, such as jerk, sliding time and sliding work, before and after optimization are compared using the proposed locking quality evaluation function. A locking characteristic test verification bench was built to verify the locking qualities before and after optimization. The results show that the proposed dynamic system simulation model can be used to accurately predict the dynamic locking process. The locking quality after optimization is significantly improved compared with the result before optimization, and the impact is significantly reduced. [ABSTRACT FROM AUTHOR]

In order to improve the braking efficiency of dual torus hydrodynamic retarder, the parameter optimization design of blade top arcs is studied. A numerical model of internal flow passage is established based on the parametric modeling method of blade top arcs. The computational fluid dynamics method is used for design of experiments with the radius and distance of blade top arcs as design variables, and the sensitivity analysis of two parameters having the effect on brake performance is made. A gradient optimization algorithm is used to get the optimum result by building an approximate model of braking torque. The influence of design parameters on internal flow field and external brake performance is analyzed, and the simulated results are compared with the experimental data. The results show that the brake performance of hydrodynamic retarder after optimization is significantly improved, the braking torque is increased by 70.8%, and the blade structure meets the strength requirement. [ABSTRACT FROM AUTHOR]

The various types of error coupling transmission mechanisms and the dimensional tolerance optimization design of multi-faceted shafting assembly are analyzed by taking the multi-faceted shafting assembly as the research object. Monte Carlo method is used to simulate the measured size of assemly ring,and the mean value of radial run-out tolerance and its distribution law are obtained. A prediction method for the radial circle run-out of variable boundary circle is proposed,and the integrated cumulative error including the coaxiality and the matching tolerance of shaft hole is established. This method is extended to the assembly error modeling of complex assembly to realize the prediction of the radial run-out tolerance in the design. With the goal of accumulating the radial runout at the end of the assembly,the average assembly accuracy,assembly reliability,and processing cost are set as constraints,and the optimization of system structure and its component tolerances is performed. Taking the design of a certain type of torque converter as an example,the feasibility and practicability of this method for predicting the cumulative radial run-out tolerance of the shaft system are verified. [ABSTRACT FROM AUTHOR]

The load fluctuation and vibration of blade should he analyzed in the design of high power den­sity and compact stamping-welded tofque converter. The simulation is based on fluid structure interaction and dynamic mesh. The load fluctuation and vibration in time domain are extracted by setting the monitoring points along the blade From inlet to outlet. Fast Fourier transform and modal analysis are used in frequency domain analysis. The analysis results indicate that the max toad fluctuation and blade vibra­tion are at the inlet of blade because of the hydraulic impact, and the amplitudes of load fluctuation and blade vibration decay along inlet to outlet at a certain speed ratio. As the speed of turbine is higher, the amplitudes also decay. The peak frequency of load fluctuation is between the second-order and third-order modals, and also the amplitude of load fluctuation decreases at higher speed ratio. [ABSTRACT FROM AUTHOR]

An optimization platform of hydraulic retarder cascade is established to optimize the parameters of the bowed blade of dual torus hydraulic retarder. The parametric modeling of single periodic flow is achieved, and the grid independence is studied to validate the credibility of simulation model. Based on CFD simulation, the design of experiments is adopted to study the influences of blade wrap angles and pressure surface radii on the brake performance. The response surface methodology is built to get the optimum parameters, and the multi-island genetic algorithm is used for global optimization design. Comparison of internal flow field and brake performance before and after optimization shows that the brake performance of hydraulic retarder with the optimum parameters is improved observably, and the braking torque is averagely increased by 42.3%. [ABSTRACT FROM AUTHOR]

A coordinated hierarchy control strategy of driving torque is proposed for the distributed electric drive tracked vehicle. The coordination control system structure is developed, which is divided into motion control layer, control allocation layer and anti-slip layer. The vehicle is considered to be an unequal over-actuated system. A master-slave multi-motor control allocation law is established. The quadratic programming method is used to design the torque optimization distribution law of in-wheel motors, and the weighted least square (WLS) method is used to solve torque distribution , which could improve adhesion margin and decrease friction loss between motor wheels and track. The anti-slip control law developed by LADRC is used to enhance the adhesive force by restricting the slip of drive wheel. Co-simulation of Matlab and RecurDyn shows that the control allocation could realize torque optimization distribution, and LADRC anti-slip controller could regulate the slip speed in steady margin, which could improve the stability and efficiency of force transfer. [ABSTRACT FROM AUTHOR]