Applied Mechanics and Materials Vol. 697

Abstract: Hydro mechanical stepless speed system is a new conbination system of hydraulic transmission and mechanical transmission, which realizes the stepless speed change through the hydraulic transmission and the mechanical transmission to reduce the speed and torque, and to improve transmission efficiency; through optimizing design, The system can realize the differential steering, increase ground clearance. In this paper, the caterpillar feeding combined harvester is the object, the system is composed by the motor, a variable pump single stage planetary gear, hydraulic machinery stepless speed walking system is of wide speed range, simple structure.

Abstract: The closed hydraulic transmission system is composed of a variable hydraulic pump, hydraulic motor, quantitative integrated valve and fuel tank and other components. The system has the advantages of compact structure, good sealing, stable transmission, high efficiency, low failure rate, it can realize the stepless speed regulation, convenient commutation, widely used in walking machinery working environment is bad, the speed of uniform.

Abstract: Cap sealing reciprocating seals are dry friction conditions, the paper separately from the main factor moving the cap seal sealing mechanism, wear mechanism, elastic modulus theoretical analysis of its sealing properties and tribological law. Mathematical model, derived cap seal stress and Von-Mises stress distribution in the contact pressure under different quality work through finite element analysis software.Keywords: Rod seal; cap seal structure; stress analysis; Finite Element Analysis.

Abstract: When the Stirling engine piston rod for reciprocating motion at a high speed under dry friction conditions, the temperature fall or pressure drop is mainly caused by uneven sealing ring deformation, increased wear and sealing performance fall. This article is introduced a cap seal rings of Stirling engine piston, study for friction and wear in theory under dynamic seal condition, and establish a rod seal test equipment to analysis the cap seal structure distortion and gauge wear in different working environments by experimental methods. Finally, come to the conclusion that when working medium pressure at 7 mpa, the cap seal performance is best.Keywords: Rod seal; cap seal structure; stress analysis

Abstract: An abnormal journal vibration occurred when a 660MW turbo generator unit was in daily operation. It was identified that rubbing vibration had taken place based on the behavior of the journal vibration and the temperature change of lubricating oil. The rubbing was located inside the bearing box between the HIP rotor and the LP rotor. However, no elimination measures had been taken in time because the damage caused by rubbing was underestimated. Few months later a full inspection revealed that the LP rotor shaft had been worn out with a 70mm wide and 28mm deep groove, which greatly weakened the strength of the LP rotor. The analysis presented here may help in diagnosing and understanding rubbing-vibration-related problems in similar situations.

Abstract: The paper analyzes the working principle of hydro-viscous speed control system, establishes the mathematical model of electro-hydraulic proportional valve and the hydro-viscous clutch. In order to solve the problem of nonlinear and improve the real-time of the hydro-viscous clutch control system, the paper applies the method of fuzzy-PID control, realizes the design and simulation of the speed-system controller in the Simulink platform of MATLAB and performs an experiment by controlling the cooling fan of tracked vehicle.

Abstract: measuring principle of dynamic unbalance and calibration process is the key point of the crankshaft production, which refers to the unbalance theory, mechanical design, sensors, and signal analysis. It is a complex and comprehensive technology. This paper mainly introduces the measuring principle of dynamic unbalance for crankshaft from theoretical side. Firstly, we will introduce the calculation theory of dynamic balancing; secondly, we will introduce the measuring system of crankshaft dynamic balancing, which includes support system and measuring system.Key words: dynamic balancing, influence coefficient method, support system, measuring system

Abstract: According to flexible connectivity of space stabilization system,This paper proposes the finite element analysis method using multiple equivalent spring connecting unit to replace the original flexible connections. And the elastic coefficient’s correspondence between the equivalent spring and the original spring were deduced. Using the equivalent spring method, the tip/tilt mirror system for finite element modeling is completed, After completion of the modal analysis, first-order resonant frequency is calculated. At last, the tip/tilt mirror system is tested in non-contact laser resonance detection system, And test results and modal analysis results were compared, and results show that the finite element modeling method of using equivalent spring connecting is effective. Provide constructive reference for subsequent tip/tilt mirror design, has a very important reference for similar projects.

Abstract: The bionic robot is of great value in research and application. In this paper, the jumping mechanism of a jumping robot is designed through imitates locusts’ jumping, which based on the principles of bionics. The model is established according to the physical structure of locusts, and the kinematic analysis of the model is done by using the virtual prototype software, ADAMS. By comparing the influence of different length on the motion, the curve of displacement, velocity, acceleration and other parameters with different length of actuator was given, as well as the position of dead point. Through analysis by using the virtual prototype software, the appropriate length of bar is confirmed. Thus, a feasible scheme for jumping mechanism of jumping robot is provided.

Abstract: Using the basic principle of heat transfer, tribology and numerical simulation, a two-dimensional heat transfer model of the three-layer composite brake pair materials were established. The temperature fields of brake pairs during the process of friction were analyzed. Applied given heat loads at different time node on the brake pair model, the temperatures of different bicycle brake pairs were compared and analyzed. Results show that the improved surface structures of brake pair have positive effect on decreasing the temperature of contact areas than that of ordinary surface structure.