Key Engineering Materials Vol. 620

Abstract: As the primary energy consumption and environmental pollution increasing seriously, green energy has been more and more got attention of researchers both at home and abroad, especially the study of solar occupies a large proportion in the development of green energy. The photovoltaic (PV) power supply system has many advantages, however, there are still problems, e.g. low voltage, low power, poor ability to resist disturbance. Around these problems, the paper designed a PV power supply control system could realize the uninterrupted power supply, including DC and AC supply. By the method of combining software with hardware, through the solar panel to the configured two pieces of battery could realize the function of fast and float charging, and the supply battery is changed by testing the battery power to load uninterrupted power supply. Moreover, when the output voltage of the solar panel is lower than the battery, the output voltage of solar panel is boosted by DC/DC circuit to make the solar panel at low pressures also to charge the battery, effectively solving the difficult solar energy in the weak power supply problem. Finally, the design of PV power supply control system not only could realize DC supply, and also AC power supply by SPWM method, which has good effect of power supply.

Abstract: Hydraulic engine mounts (HEMs) are important vibration isolation parts in vehicle powertrain mounting systems. The structural parameters of HEMs are the main factors which determine their vibration isolation characteristics. It is of great significance to discover the influences of the structure parameters on their vibration isolation characteristics in the design and study of HEMs. HEMs with different rubber materials, lengths and cross-sectional areas of the inertia tracks are designed and manufactured, and their frequency response characteristics are investigated by experimental and analytical methods. The influences of these structural parameters on the vibration isolation characteristics of HEMs are educed. The analytical methods and conclusions are instructive for the design and tuning of the vibration isolation characteristics of HEMs.

Abstract: The working principle of turbodrill is discussed in this paper, through discussing the structural characteristics of the turbine shaft, it is pointed out that the part where minimum axis diameter of the turbine shaft is, the hollow area of the turbine shaft, and the hollow place where is the thread at the bottom of the turbine shaft are the three most dangerous parts. With the structure of the turbine shaft of 195mm turbodrill as an example, the strength calculation methods and calculation results of the three most dangerous parts are given. Through comparative analysis on various advanced international parametric design platform, the SolidWorks is chosen as a basic platform for parameterization, this paper puts forward the parametric method of 195mm turbine shaft and the series design of turbine shaft have been achieved. The strength calculation method and parametric method of the turbine shaft have been developed and used in the series design in Yangtze university of China.

Abstract: In this paper, the relationship of the driving parameters and the movement of stick-slip driving was studied. Firstly, the research status and the principle of stick-slip driving was introduced. Secondly, the math model of the every step displacement and velocity of stick-slip driving was built. By using mathematical models, the relationship curve of the every step displacement and the step time was received through the simulation in Matlab software. Furthermore, in corroboration of the math model, the prototype was designed and the experiment system was built. From the testing of stick-slip prototype, the step displacement in every step time was tested 20 times and the relationship curve of the average every step displacement and step time was obtained. The simulation results are validated by the testing results and the method of reducing the time step to adjust the stick-slip driving step displacement and velocity were proved. In the future, a greater drive power should be researched for improving the movement performance of the stick-slip driving.

Abstract: For the maximum output power varies with changes in load characteristics match the characteristics of solar cells in photovoltaic power generation system, the system runs through dynamic MPPT maximum power of self-optimizing process to achieve power from the PV charge control match. First, the output characteristic simulation analysis of the solar load resistive, capacitive load showed that solar power batteries for load matching efficiency is higher than in a purely resistive load. Then, using the improved algorithm for variable step size perturbation and observation of the received output power of solar power and load matching control, experiments showed that the optimum operating point of the circuit can control the real-time monitoring of solar cells and load. The output power from the battery load matching circuit to match the time working in the best working condition, if the energy is surplus or shortage, the system can control dynamic self-optimizing adjustment to charge, which leads to batteries absorbed power increasing and the efficiency of solar energy collection improving.

Abstract: Gear honing processing is a kind of processing method which belongs to the point-contact generating gear finishing. Its movement form is equivalent to a pair of gears transmission which the surface of the gear-honing-tool is adhered a layer of grinding grain. When it works in rolling processing, the contact-point between the workpiece and gear-honing-tool is moving. Then the moving point becomes a line in the space, and with the gear-honing-tool being in axial play, a standard flank of tooth is finished. Using the gear meshing principle, kinematics model of relative sliding velocity in the contact-point between the workpiece and tools is established, based on which the contact-line equation. and acceleration equation. at the contact-point are derived. The contact-line is solved in a given parameters of the workpiece and tool in MATLAB. The theoretical derivation and experimental results show that the speed in diverse along the direction of the tooth depth is the main reason for the roughness value and surface texture of workpiece. The acceleration of contact-line at the tooth flank is different, and it is leading reason that the processed workpiece gears appear profile distortion. Finally, the testing system is established for researching honing gear process. It is showed in the results that the acceleration difference can lead to the CBN abrasive falling away from gear honing tool, and even the "anti-cutting" phenomenon.

Abstract: Firstly a three degrees of freedom micro-positioning stage constructed by flexure hinges is designed, and the simplified model of the stage is established. Secondly, the stiffness of the stage along X, Y direction or around Z direction is deduced by structural mechanics. The difference between finite element method and theory value is less than 7%, so it shows the theory analysis is feasible, further more, stress of the moving stage is analyzed, and the effect curve of the key parameters to the stiffness and stress is obtained. It can be concluded that the stiffness and stress mainly related with the flexure hinge length L and width t, thus it provide a theoretical basis for three-dimensional micro-positioning stage design.

Abstract: Electronic power steering (EPS) system is a critical component for vehicle safety driving. The damping force of automobile steering is decreased at high speeds, so the driving feel is floating. When vehicle suspension shock and a front wheel sensitive to road counterforce it is relation with the driver safety. For the subject of vehicle stability at high speed, an EPS system control strategy of stability has been presented. In order to keep driving feel, when the steering resistance decrease an elastic damping will be increased. Current follow control technique is introduced, and the torque sensor can estimate the vehicle state. This method can be verified by the experiment.

Abstract: In this thesis, by changing the filter overflow tube insertion depth of spin streaming filter, combined with the existing drip irrigation equipment change the structure parameters of spin streaming filter. Using Fluent software to choose reasonable turbulence model for numerical simulation analysis, contrastive research on the field test was carried on, reveals the relationship between the internal flow field pressure and the flow rate. The sediment production increased before they are reduced with the increase of the overflow tube insertion depth. It should choose the optimal insertion depth according to the specific use and usage model of hydrocyclone in actually use. The variation trend of internal flow field pressure and the flow rate when selected structural parameters changed are also analyzed. With the increase of insertion depth, the axial velocity and radial velocity of sand and water inside the hydrocyclone shows the tendency of decrease. Furthermore, the field experiment verifies the simulation result, thus proving the feasibility of using Fluent computational fluid dynamics software to simulate the internal flow field of the spin streaming filter. The research results will provide referential basis for the design and application of the drip filter system.

Abstract: Different substrates grease composition due to differences in their varying degrees of change in viscosity after shearing studied the rheological properties of three different substrates grease. Used AR2000ex rheometer, investigated the effects of different sessions on the rheological properties of the grease. It was found that the stability of lithium grease from the grease either stops working, or their work situation by cutting lubrication properties, are superior to calcium-based grease and urea-based grease. Urea-based grease on the shear sensitivity is smaller relatively than lithium and the recovery of viscosity after being subjected to continuous shear weak, easily lost during use based the grease flow curves with Herschel-Bulkley model, and the impact performance of the grease thixotropic grease is yield stress.