Cylindrical rollers are important elements of bearings,and their machining accuracy and consistency affect the bearing quality.Using a GCr15 cylindrical roller ofФ11×12 as the processing object in this study,the...Cylindrical rollers are important elements of bearings,and their machining accuracy and consistency affect the bearing quality.Using a GCr15 cylindrical roller ofФ11×12 as the processing object in this study,the effects of loading pressure,abrasive concentration,and speed combination on cylindrical roller machining precision were investigated using the orthogonal experimental design method on a double-side eccentric pendulum lapping and polishing machine.The machining parameters of the lapping stage were optimized,and the lapping optimal process parameters were determined by S/N response analysis and analysis of variance(ANOVA).The results show that when the experiment was optimized using loading pressure of 10 N/roller,abrasive concentrationof 20.0 wt%,and rotational speed combination,the material removal rate(MRR)of cylindrical roller reached 0.0896μm/min;the average roughness of the batch decreased from 0.056μm to 0.027μm,51.8%lower than the original batch average roughness,and the deviation decreased from the initial 0.022μm to 0.014μm;the batch average roundness error decreased from 0.47μm to 0.28μm,40.4%lower than the original batch average roundness error,and the deviation decreased from the initial 0.19μm to 0.038μm;and the batch average diameter variation decreased from 4.5μm to about 3.6μm,20%lower than the original batch average diameter variation.The double-side eccentric lapping of cylinder rollers does not only lead to improvement in the surface quality and shape accuracy of rollers,but also improvement in the batch consistency.展开更多
In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know u...In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know under what conditions the water vapor has higher heat transfer efficiency in the semi-circular cylinder and more sufficient liquid phase transition, and under what conditions the quantity of heat transferred can be exactly controlled, we carried out relevant work. Based on the analysis of two-phase heat transfer of rotating body, a three-dimension model of garbage dryer is established. Then, the commercial CFD software ANSYS Fluent is used to simulate the two-phase flow in the semi-circular cylinder, and the simulation calculation is carried out. Finally, the theoretical calculation results are verified by experiments. Calculated by the simulation results analysis: according to the industrial use of setting conditions, simulation calculation results can achieve convergence, namely water vapor through the pipe wall heat conduction. Finally condense into liquid water, and to ensure that the liquid cavity in the body has a higher volume fraction, water vapor phase change rate is of more than 90%, the Nusselt number of the heat transfer surface is 60 to 300.展开更多
为了提高异型滚子弧面凸轮减速机构设计效率、规范设计体系,提出一种基于NX二次开发的参数化设计方法,并开发了设计系统。依据空间几何理论和共轭曲面原理,推导了圆柱滚子、圆锥滚子、球锥滚子、鼓形滚子、球滚子5种典型类型的异型滚子...为了提高异型滚子弧面凸轮减速机构设计效率、规范设计体系,提出一种基于NX二次开发的参数化设计方法,并开发了设计系统。依据空间几何理论和共轭曲面原理,推导了圆柱滚子、圆锥滚子、球锥滚子、鼓形滚子、球滚子5种典型类型的异型滚子及弧面凸轮工作廓面方程;提取关键设计参数,利用NX二次开发工具开发人机交互设计菜单和对话框,结合NX Open C/C++API和Visual Studio编译环境,开发异型滚子弧面凸轮减速机构参数化设计系统,并根据机构中各部件之间的装配约束关系,开发了自动装配功能。系统验证表明,开发的整套系统可以满足用户的个性化设计需求,有助于实现异型滚子弧面凸轮减速机构设计流程的规范化、标准化,实现快速设计与修改,缩短设计周期。展开更多
基金supported by National Natural Science Foundation of China (Grant No.51175468,U1401247)Public Welfare Industry Project of Zhejiang Provincial Science and Technology Department (Grant no.20160069)
文摘Cylindrical rollers are important elements of bearings,and their machining accuracy and consistency affect the bearing quality.Using a GCr15 cylindrical roller ofФ11×12 as the processing object in this study,the effects of loading pressure,abrasive concentration,and speed combination on cylindrical roller machining precision were investigated using the orthogonal experimental design method on a double-side eccentric pendulum lapping and polishing machine.The machining parameters of the lapping stage were optimized,and the lapping optimal process parameters were determined by S/N response analysis and analysis of variance(ANOVA).The results show that when the experiment was optimized using loading pressure of 10 N/roller,abrasive concentrationof 20.0 wt%,and rotational speed combination,the material removal rate(MRR)of cylindrical roller reached 0.0896μm/min;the average roughness of the batch decreased from 0.056μm to 0.027μm,51.8%lower than the original batch average roughness,and the deviation decreased from the initial 0.022μm to 0.014μm;the batch average roundness error decreased from 0.47μm to 0.28μm,40.4%lower than the original batch average roundness error,and the deviation decreased from the initial 0.19μm to 0.038μm;and the batch average diameter variation decreased from 4.5μm to about 3.6μm,20%lower than the original batch average diameter variation.The double-side eccentric lapping of cylinder rollers does not only lead to improvement in the surface quality and shape accuracy of rollers,but also improvement in the batch consistency.
文摘In recent years, the new type of tumble waste dryer has been promoted and developed. Heat generation through phase transition is an environmental, friendly and efficient heat transfer drying method. In order to know under what conditions the water vapor has higher heat transfer efficiency in the semi-circular cylinder and more sufficient liquid phase transition, and under what conditions the quantity of heat transferred can be exactly controlled, we carried out relevant work. Based on the analysis of two-phase heat transfer of rotating body, a three-dimension model of garbage dryer is established. Then, the commercial CFD software ANSYS Fluent is used to simulate the two-phase flow in the semi-circular cylinder, and the simulation calculation is carried out. Finally, the theoretical calculation results are verified by experiments. Calculated by the simulation results analysis: according to the industrial use of setting conditions, simulation calculation results can achieve convergence, namely water vapor through the pipe wall heat conduction. Finally condense into liquid water, and to ensure that the liquid cavity in the body has a higher volume fraction, water vapor phase change rate is of more than 90%, the Nusselt number of the heat transfer surface is 60 to 300.
文摘为了提高异型滚子弧面凸轮减速机构设计效率、规范设计体系,提出一种基于NX二次开发的参数化设计方法,并开发了设计系统。依据空间几何理论和共轭曲面原理,推导了圆柱滚子、圆锥滚子、球锥滚子、鼓形滚子、球滚子5种典型类型的异型滚子及弧面凸轮工作廓面方程;提取关键设计参数,利用NX二次开发工具开发人机交互设计菜单和对话框,结合NX Open C/C++API和Visual Studio编译环境,开发异型滚子弧面凸轮减速机构参数化设计系统,并根据机构中各部件之间的装配约束关系,开发了自动装配功能。系统验证表明,开发的整套系统可以满足用户的个性化设计需求,有助于实现异型滚子弧面凸轮减速机构设计流程的规范化、标准化,实现快速设计与修改,缩短设计周期。
