新型润滑脂泵送系统设计与性能研究

发布时间：2018-05-19 17:48

本文选题：润滑脂 + 输送系统　；参考：《中国矿业大学》2015年硕士论文

【摘要】：润滑脂是一种由基础油、稠化剂、添加剂混合而成的半固态机械润滑剂,具有极压、抗磨、密封性好等良好的润滑性能,因而广泛应用于低速重载装备领域的开式润滑系统中。现代机械装备的大型化、重载化、自动化趋势对脂润滑的可靠性要求越来越高,而润滑脂粘稠度大、输送困难,使得目前的集中供脂装置难以可靠地完成定时、定量的供脂任务。深入研究润滑脂输送系统对于保障机械设备润滑、降低磨损具有重要意义。为解决这一难题,本文首先研究了润滑脂的微观结构及在圆管中的流动特性,为输送系统的研制提供了理论基础;然后提出了润滑脂泵送系统设计方案,进行了输送系统的理论及仿真分析;最后通过实验研究分析验证了润滑脂泵送系统的可行性及工作可靠性。主要研究结果如下:(1)对润滑脂的流变特性机理、主要指标及润滑脂运动基本方程进行了系统分析,建立了基于圆管流动条件下润滑脂流动特性模型。通过对3#锂基润滑脂进行流变实验得出了润滑脂拟合流变方程,并借助拟合参数进行了润滑脂圆管流动行为参数的预测。(2)提出了采用曲轴驱动并将液压缸与润滑脂泵相结合进行输送的润滑脂泵送系统方案并建立了润滑脂泵实体模型,分析得出了曲轴结构优化方案并进行了曲轴应力应变分析。运用AMESim软件建立了系统仿真模型,分析了润滑脂泵送系统的输出压力、流量特性以及曲轴、活塞动力学特性。结果表明:流量曲线以及曲轴、活塞运动曲线均与理论值基本吻合,流量曲线波动达12%,能够满足系统设计要求;输出压力与流量曲线表现平稳,满足了系统对输出性能稳定的要求;系统表现出了良好的稳定性。(3)运用FLUENT软件分析了润滑脂在泵体中的流动行为,得出吸排脂过程中润滑脂腔压力、速度、粘度分布云图。结果表明:活塞移动初始及结束阶段润滑脂腔内无明显压力冲击现象,润滑脂泵工作稳定性良好;活塞移动时管壁处润滑脂因受剪切作用而粘度降低,这种剪切稀化特性有利于泵体对润滑脂的输送;对于进脂口与润滑脂腔下交界处出现压力和速度突变问题,给出了优化措施。(4)搭建了润滑脂泵送系统模拟试验台,对系统的输出流量、输出压力特性以及液压缸与润滑脂泵协同工作可靠性方面进行了实验验证。结果表明:润滑脂的输出压力及输出流量值均与理论及仿真结果吻合,完全满足工况要求;增压缸与泵体之间协同工作效果可靠,系统工作效率高。
[Abstract]:Grease is a semi-solid mechanical lubricant mixed with base oil, thickener and additive. It has excellent lubricating properties such as extreme pressure, anti-wear and good sealing, so it is widely used in open lubricating system in the field of low speed and heavy load equipment. The trend of large scale, heavy load and automation of modern machinery and equipment requires higher and higher reliability of grease lubrication. However, the high viscosity of grease and difficulty in conveying make it difficult for the current centralized grease supply device to reliably complete the timing. Quantitative fat supply. It is of great significance to study the grease conveying system to guarantee the lubrication of mechanical equipment and to reduce the wear. In order to solve this problem, this paper first studies the microstructure of grease and the flow characteristics of the grease in the pipe, which provides the theoretical basis for the development of the conveying system, and then puts forward the design scheme of the grease pumping system. Finally, the feasibility and reliability of the grease pumping system are verified by the experimental research and analysis. The main results are as follows: (1) the rheological mechanism, main indexes and basic equations of lubricating grease motion are systematically analyzed, and the flow characteristic model of lubricating grease under the condition of pipe flow is established. The rheological equation of the grease was obtained by the rheological test of the lithium-base grease. With the aid of fitting parameters, the prediction of the flow behavior parameters of lubricating grease pipe is carried out. (2) the scheme of grease pumping system driven by crankshaft and the combination of hydraulic cylinder and grease pump is put forward, and the solid model of grease pump is established. The optimization scheme of crankshaft structure is obtained and the stress-strain analysis of crankshaft is carried out. The simulation model of the system is established by using AMESim software. The output pressure, flow rate, crankshaft and piston dynamics of the grease pumping system are analyzed. The results show that the flow curve, crankshaft and piston motion curve are basically consistent with the theoretical value, the flow curve fluctuates to 12, which can meet the system design requirements, and the output pressure and flow curves are stable. The system shows good stability. The flow behavior of lubricating grease in pump body is analyzed by FLUENT software, and the distribution of pressure, velocity and viscosity of grease cavity in the process of suction and discharging is obtained. The results show that there is no obvious pressure shock phenomenon in the grease cavity during the initial and end stages of piston movement, and the grease pump has good working stability, and the viscosity of the lubricating grease at the pipe wall decreases because of the shear action when the piston moves. This shearing thinning characteristic is advantageous to the pump body conveying the grease; for the sudden change of pressure and velocity at the junction between the inlet and the grease cavity, the optimization measures are given. 4) A grease pumping system simulation test-bed is built. The system output flow, output pressure characteristics and the reliability of the hydraulic cylinder and lubricating grease pump are verified experimentally. The results show that the output pressure and the output flow value of the grease are in agreement with the theoretical and simulation results, which fully meet the requirements of the working conditions, and the cooperative working effect between the pressurized cylinder and the pump body is reliable, and the system work efficiency is high.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE626.4;TE964

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