| Travelling motor is consisted with swash plate axial piston motor, controlling valves, planetary gear reducer mechanism, which is widely used in the field of constructive machinery, ships, agricultural machinery, aircrafts and so on. The efficiency of hydraulic system on constructive machinery is very low, and the scholars at home and abroad respectively foucus on the hydraulic system design, the selection of hydraulic component with high efficiency, energy regeneration reserve and power matching and so on. Among them, the effect of improving the efficiency of pump and motor is more obvious, which is in favor of the goals of low cost, low pollution and high energy efficiency.Among all the power loss of travelling motor, the power loss resulted from friction of valve plate can contribute to about5%of all the power loss, and the power loss resulted from leakage can contribute to about3%of all the power loss. So research on how to reduce the power loss caused by the valve plate, is the key to improve the efficiency of the travelling motor. Domestic and foreign scholars have respectively devoted their time to the research on surface formation and texture technology, new materials and surface coating technology, advanced manufacturing technology. And the dissertation leads the international fluid power transmission field frontier, and machines micro-hemispherical texture on the top and bottom dead zone on the valve plate of travelling motor using surface formation and texture technology, in order to low friction and optimize the force of travelling motor cylinder block. Furthermore, it established the mathematic model of micro-hemispherical texture valve plate frictional pair wedge oil film, and carried out numerical calculation and analysis. It is shown that the method of machining micro-hemispherical texture on the surface of valve plate has potential to low friction and optimize the force of travelling motor cylinder block.American famous scholars Ivantysynova Monika team and the South Korean scholars Shin J H team researched the friction reduction of the micro-wave texture on the overall surface of valve plate, on the other hand, Germany famous scholars Hubertus Murrenhoff team researched the friction reduction of the micro-ellipsoidal texture on the overall surface of valve plate, they found that the cylinder block can produce vibration phenomenon, but they didn’t present relevant mechanism analysis. In this paper, the author for the first time analysed the mechanism of vibration on cylinder block, and issued the concept of "Stable oil film thickness of micro-hemispherical texture valve plate frictional pair" and "Critical oil film thickness", which was used to judge the stable operation of micro-hemispherical texture valve plate frictional pair between valve plate and cylinder block, and designed out the first contact type lubricating film thickness measuring device with low cost, and successfully tested out the lubricating film thickness of micro-hemispherical texture valve plate frictional pair, and presented the relevant mechanism analysis of micro-hemispherical texture valve plate frictional pair between valve plate and cylinder block.This paper will develop the travelling motor with high efficiency, long life. This dissertation will focuse on the frictional performance of valve plate with micro-hemispherical texture, the pressure distribution of inclined oil film resulted from valve plate with micro-hemispherical texture, the vibration mechanism of cylinder block on travelling motor with micro-hemispherical texture valve plate, and the efficiency performance of travelling motor with micro-hemispherical texture valve plate, furthermore, the test applicance of frictional performance on travelling motor is designed out. Moreover, it can provide reference for the research and development of micro-hemispherical texture valve plate on travelling motor reducing friction. On the other hand, it keeps up with the current national theory of energy saving, environment protecting.The thesis is mainly divided into the following parts:In Chapter1, current research status of valve plate with micro-texture on axial piston pump or motor is introduced, American famous scholars Ivantysynova Monika team and the South Korean scholars Shin J H team researched the friction reduction of the micro-wave texture on the overall surface of valve plate, on the other hand, Germany famous scholars Hubertus Murrenhoff team researched the friction reduction of the micro-ellipsoidal texture on the overall surface of valve plate, and research status of reducing friction on micro texture at home and abroad field of tribology is introduced, and research status of mechanical sealing vibration at home and abroad field of tribology is introduced, considering the similarity of mechanical seal vibration model and the travelling motor cylinder block vibration model. And research status and existing problems of micro texture frictional pair of the axial piston pump or motor is introduced. The main research objects and academic significances of this dissertation on travelling motor were pointed out at last.Laser machining micro-hemispherical texture is most suitable for the travelling motor on the top and bottom dead zone on the valve plate.The famous scholar research on different kinds of micro-hemispherical texture, including cube, triangular, cylinder, wavy, hemispherical micro-texture, only make a comparative analysis of the characteristics of the oil film load capacity to select suitable micro-texture for travelling motor valve plate. At last, the laser machining micro-hemispherical texture is most suitable for the travelling motor on the top and bottom dead zone on the valve plate.American famous scholars Ivantysynova Monika team and the South Korean scholars Shin J H team researched the friction reduction of the micro-wave texture on the overall surface of valve plate, on the other hand, Germany famous scholars Hubertus Murrenhoff team researched the friction reduction of the micro-ellipsoidal texture on the overall surface of valve plate, they found that the cylinder block can produce vibration phenomenon, because the micro texture processed on the high and low pressure chamber sealing tape of valve plate on the swash plate axial piston pump will increase the unbalanced push torque of the swash plate axial piston pump cylinder block. Swash plate axial piston pump cylinder block rotating about orthogonal coordinate diameter angle swing amplitude could be more serious, and is not conducive to the stability of swash plate axial piston pump cylinder block. So we need to try to change the micro texture distribution on the valve plate surface, in the premise of reducing the cylinder block vibration, and also improving the oil film load capacity of micro texture in order to reduce friction and wear, optimize the force of travelling motor cylinder block. so the dissertion tries to machine micro-hemispherical texture the top and bottom dead zone on the valve plate of travelling motor in order to reduce friction and wear, optimize the force of travelling motor cylinder block.Micro-hemispherical texture are machined on the top and bottom dead zone on the valve plate of the travelling motor. With the structural parameters changing, the frictional performance of micro-hemispherical texture valve plate frictional pair need to study. So in the chapter2, the mathematic model of cube, triangular, cylinder, wavy, hemispherical micro-texture governing equation is established, and make a comparative analysis of the characteristics of the oil film load capacity to select suitable micro-texture for travelling motor valve plate, moreover, the mathematic model of micro-hemispherical texture valve plate frictional pair wedge oil film governing equation and oil film thickness governing equation were established, and numerical calculation and analysis were carried out. The sealing width, hydraulic oil viscosity, cylinder rotatry, the initial oil film thickness, the cylinder inclined angle on the impact of pressure distribution, parameters of performance, coordinate and so on.Optimization design of micro-hemispherical texture can obviously reduce the valve plate frictional coefficient and wear. After the determination of valve plate structural parameters, the structural parameters and distribution style of micro-hemispherical texture on the valve plate will play an important role on the frictional performance of micro-hemispherical texture valve plate frictional pair and need to optimize it. So in Chapter3, the mathematic model of micro-hemispherical texture valve plate frictional pair wedge oil film governing equation and oil film thickness governing equation were established, and numerical calculation and analysis were carried out. Moreover, the influence of micro-hemispherical texture diameter, depth, area ratio on the lubricating film pressure distribution, pushing force, pushing moment, friction, frictional coefficient, frictional torque, average oil film stiffness were analysed. On the other hand, the test applicance of frictional performance on travelling motor valve plate was designed out, and the valve plate with different micro-hemispherical texture were machined and carried out a test on their frictional performance. It is shown that the optimization design of micro-hemispherical texture on the surface of valve plate can obviously low friction and has potential to increase efficiency.When the "Stable oil film thickness of micro-hemispherical texture valve plate frictional pair" is less than the "Critical oil film thickness", the vibration, of cylinder block resulted from micro-hemispherical texture will disappear. American famous scholars Ivantysynova Monika team and the South Korean scholars Shin J H team researched the friction reduction of the micro-wave texture on the overall surface of valve plate, on the other hand, Germany famous scholars Hubertus Murrenhoff team researched the friction reduction of the micro-ellipsoidal texture on the overall surface of valve plate, they found that the cylinder block could produce vibration phenomenon, but they didn’t present relevant mechanism analysis, which seriously blocks the direction of this research continue to advance. In this paper, the author analysed the mechanism of vibration on cylinder block. So in Chapter4, the pressure distribution, loading force, torque of cylinder block were analyzed,and the vibration equation of cylinder block based the Reynolds equation about micro-hemispherical texture valve plate wedge oil film was established. Based on the minimum power loss, the best solution under the condition of oil film thickness was calculated, at the same time, using the root locus method to judge the stability of cylinder block. Furthermore, the contact type lubricating film thickness measuring device with low cost was designed out, and successfully the lubricating film thickness and temperature of micro-hemispherical texture valve plate frictional pair were tested out, it is found that the effect of micro-hemispherical texture to improve the lubricating film thickness is not obvious, but can reduce the lubricating film temperature.The micro-hemispherical texture machined on the surface of valve plate could optimize the fore of travelling motor cylinder block under some operational condition, and reduce the degree of wear around the micro-hemispherical texture.The impact of micro-hemispherical texture on the surface of valve plate on the overall efficieny of travelling motor, and the wear and frictional performance, should be both confirmed. So in Chapter5, micro-hemispherical texture machined on the surface of valve plate could have the potential to improve the overall efficiency of travelling motor under some operational condition, which was simulated and analysed, and the performance test platform with high resolution of travelling motor was established, and the overall efficiency of travelling motor with different micro-hemispherical texture valve plate was tested and analysed. It is shown that micro-hemispherical texture machined on the surface of valve plate could have the potential to improve the overall efficiency of travelling motor under some operational condition. On the other hand, Through the electron microscopy observation on the micro-hemispherical texture machined on the surface of valve plate, it is shown that micro-hemispherical texture machined on the surface of valve plate could reduce the degree of wear around the micro-hemispherical texture.In Chapter6, the research work of this dissertation was firstly summarized, and some advices on further research work were then presented. |
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