Influence of Process Parameters on Screw Rotor Profiles

A model‐based simulation is presented to analyze the influence of manufacturing process variations on rotor profile. The simulation servers as a virtual machine tool to virtually machine rotors. By varying machine parameters within their tolerance bands, the simulation predicts rotor profile errors caused by various process parameter errors. The input to the simulation includes designed rotor profile data, lead, diameters, and machine setup and machine capability expressed in terms of parameter accuracy. The output is the ‘manufactured’ rotor profile. The simulation can be used to evaluate if a machine or process is capable of making the designed profile with the required tolerance. It can also be used to check and validate rotor clearance distributions in the design stage.     

多级双作用滚柱转子泵转子槽型线的分析

通过对多级双作用滚柱转子泵运转时滚柱受力的分析,建立了滚柱运动受力平衡方程,首次推导出该泵转子槽型线的计算公式。通过实例计算及分析,按滑动摩擦为最小原则,选择最优槽型夹角,消除闭死容积,改善滚柱运动受力状况,为今后该泵转子槽型线的优化设计指明了方向。     

面向制造的曲面设计系统

为了支持面向制造的曲面设计,提出了一个基于计算机辅助设计／计算机辅助制造系统的嵌人式计算平台,该计算平台主要包括约束信息建模和可制造性分析2个功能模块。通过对曲面可制造性判据的抽象,建立了应用信息模型,用于从曲面几何形状中提取制造约束信息。应用于曲面加工问题,给出了根据约束信息计算可行刀具方向的具体方法。面向模具零件分型曲面的设计,建立了可制造性分析工具。针对一个雕塑曲面零件设计实例,通过对模具分型方向和加工约束进行分析,给出了可行的分型曲面设计结果,验证了所提出的曲面可制造性分析方法的可行性。     

Automated design system for a rotor with an ellipse lobe profile

An internal lobe pump (ILP) is suitable for machine tool oil hydraulics, automotive engines, compressors, and various other devices. In particular, the ILP is an essential component of an automotive engine, used to feed lubricant oil through the system. The main components of an ILP are its rotors. The outer rotor is typically characterized by lobes with an elliptical shape, and the inner rotor profile is a conjugate to the outer profile. This paper describes a theoretical analysis of an ILP and the development of an integrated automated system for rotor design. This system is composed of three main modules and has been developed using AutoLISP for the AutoCAD program. The system generates a new lobe profile and automatically calculates flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis can enable oil pump designers and manufacturers to become more efficient.     

REDUCE THE INFLUENCE OF PROCESS ERRORS ON ROTOR PROFILE BY OPTIMIZING ROTOR OFFSET ANGLE

The clearances between paired rotors are leakage channels that reduce compressor efficiency. A significant portion of the total clearance is allocated to account for profile deviations caused by various manufacturing inaccuracies. The accuracy of the manufactured rotor profile is maintained by both the machine tool motion accuracy and the tool profile accuracy. For the same machine tool motion accuracy and tool profile accuracy, the manufactured rotor profile errors also depend on the offset angle, which is the orientation of the rotor profile while it is under machining. This paper is concerned with the selection of the offset angle to reduce the influence of process errors on the rotor profile.     

REDUCE THE INFLUENCE OF PROCESS ERRORS ON ROTOR PROFILE BY OPTIMIZING ROTOR OFFSET ANGLE

Abstract

The clearances between paired rotors are leakage channels that reduce compressor efficiency. A significant portion of the total clearance is allocated to account for profile deviations caused by various manufacturing inaccuracies. The accuracy of the manufactured rotor profile is maintained by both the machine tool motion accuracy and the tool profile accuracy. For the same machine tool motion accuracy and tool profile accuracy, the manufactured rotor profile errors also depend on the offset angle, which is the orientation of the rotor profile while it is under machining. This paper is concerned with the selection of the offset angle to reduce the influence of process errors on the rotor profile.     

产品可制造性逐步评价方法

提出一种面向并行工程的产品可制造性逐步评价方法,其评价对象可以是产品详细设计阶段的不完整的特征模型,因而可在设计过程中的任一时刻进行可制造性评价。为了保证评价方法的连贯性和评价速度,仅对前一次评价之后可能产生新的可制造性问题的特征进行评价。对产品设计过程中的特征的改变状态进行了研究,提出在产品设计过程中确定特征之间可制造性影响关系的方法,并通过影响关系找出确需进行评价的特征集合,然后采用基于规则的方法来评价特征的可制造性。     

螺杆压缩机转子成形砂轮刃形计算

针对给出任意转子型线时转子齿面加工的成形砂轮刃形设计,利用螺杆转子加工过程中转子和砂轮的相对位置关系,通过对转子型线坐标系的旋转变换,建立空间转子坐标系和成形砂轮坐标系之间的几何映射关系;基于啮合原理,建立转子齿面与成形砂轮的接触线方程,并给出解析和离散两种转子型线表达方式的刃形求解方法。在此基础上,根据转子砂轮之间的设计间隙,通过对接触线沿转子齿面法向进行偏置,获得了修整后的砂轮等距齿面刃形,避免了传统修整方法导致的法向齿间间隙不均等问题。加工结果表明,该方法能够满足螺杆转子的加工精度要求,是一种有效的螺杆转子齿面成形砂轮的刃形设计方法,并可推广应用于其他螺旋面成形砂轮或盘形铣刀的刃形设计。     

A manufacturability advisor for spun and rollformed sheet metal components

In today’s manufacturing scenario, accounting for manufacturability considerations at the product design stage is not an option but a necessity. When CAD/CAM tools are used to reduce design lead times, accounting for manufacturing process related considerations implicitly is often difficult. Availability of manufacturability advisor systems that analyze part geometry and other product related information for ease of manufacturing could be a solution to this problem. The purpose of a manufacturability assessment is to give feedback to the designer in order to make the product/process more effective. Present research is concerned with the development of an automated manufacturability advisor for sheet metal components. Unlike most of the work done in the past that concentrated on bending and other forming processes, present work deals with sheet metal components manufactured by two different processes, namely “spinning” and “rollforming”. Effectiveness of the proposed manufacturability advisor is demonstrated by taking the number of industrial parts as examples.     

并行工程下基于特征的零件可制造性研究

结合并行工程的思想，对零件可制造性进行较详细的分析，提出并行工程环境下基于特征的可制造性分析方法，研究并建立基于特征的可制造性零件定义模型及评价体系，全面合理地对零件的可制造性进行评价和反馈，从而指导产品设计。最后以涡轮叶片榫头特征的可制造性分析为应用实例，说明该方法的有效性和实用性。     

Detecting re-design area for increasing manufacturability of drilling and three-axis pocketing operations

The intensive competition has forced the manufacturing industry to improve product quality and production efficiency, and meanwhile reduce production cost. Detecting potential manufacturability problems in early design stages would prevent unnecessary cost involved in re-work and/or re-design activities at later manufacturing stages. This paper presents an algorithm for determining re-design areas to feedback the designer when the design model involves machining holes and pockets using a three-axis computer numerical control machine. The algorithm takes into account the various sizes of tools and tool holders, and therefore allows a designer to test the manufacturability of their available cutters on their design models. A color-based obstacle-detecting method, based on layer-slicing of re-design areas, helps a designer to re-evaluate a design model for increasing manufacturability. Practical examples are provided as the output of the process.     

基于流体仿真的双螺杆压缩机转子型线研究

阴阳转子型线设计时存在参数修改频繁、性能实验搭建不便等问题,影响了转子型线设计效率的提高,针对以上问题,提出将 NURBS曲线和流体仿真技术应用于双螺杆压缩机转子型线设计中的新思路。以单边不对称摆线-销齿圆弧式转子型线为研究对象,开发了新型双螺杆转子型线。应用NURBS曲线构建了螺杆转子的齿廓线;建立了双螺杆压缩机原型线与新型线流场仿真模型,运用Fluent软件模拟了其在工作转速下压强与流速的分布规律。由仿真结果对新型线设计的合理性进行了预判,并为新型线的改进优化直至获得性能优良的双螺杆压缩机阴阳转子提供了参考依据。     

基于特征Agent的并行设计系统

并行工程的主要目标之一在于对产品和过程进行并行评价,以缩短产品上市时间和降低产品成本。为了有效地在产品的设计过程中对产品的可制造性进行评价,本文提出了特征Ａｇｅｎｔ的概念。特征Ａｇｅｎｔ在自身状态或者外界环境发生相关变化时,实时地进行可制造性评价,给设计者提供反馈意见,从而有助于改善产品设计质量。在特征Ａｇｅｎｔ的基础上,文中介绍了一种由多Ａｇｅｎｔ构成的并行设计系统     

罗茨泵转子线型简明设计

罗茨真空泵转子是由两个8字型转子组成,同步反向运转而互不干涉。文中通过介绍渐开线定义和性质,归纳出一种转子线形的简明设计方法,工程运用中具有实际意义。     

罗茨机械增压器渐开线型转子型线的改进研究

针对传统渐开线罗茨转子存在参数干涉和啮合不平稳的问题,采用圆弧和圆弧包络线代替销齿圆弧,对传统渐开线转子型线进行改进设计,提出新型圆弧包络线-渐开线罗茨转子型线。以微分几何和啮合原理为基础,推导了改进转子组成型线的参数方程,构建出三叶和四叶改进转子型线。面积利用系数和啮合特性对比分析表明:改进后的转子型线,在相同结构尺寸下面积利用系数增大、啮合重合度明显提高,以四叶转子为例,面积利用系数增大12.3%、啮合重合度提高30.7%;改进后的转子由齿顶圆弧与齿根圆弧包络线连续的点啮合逐步过渡到渐开线部分啮合,啮合平稳性好。为新型转子的数字化设计及运动分析提供理论依据,同时为罗茨机械增压器的低噪声设计提供参考。     

螺杆压缩机转子型线的优化设计

设计了一种新型螺杆压缩机转子型线，利用Hpms型线处理软件，对设计的转子型线进行优化处理，以适合于转子的磨削加工。通过对加工出的转子型线进行检测和分析。表明转子型线的优化设计是成功的，达到了设计要求。     

基于加工仿真的立铣刀三维参数化设计

基于CATIA软件平台进行二次开发,开发出基于加工仿真的高速立铣刀三维参数化设计的CAD软件系统。设计人员输入立铣刀的使用参数和主要结构参数,根据系统的数据库和相关程序自动生成立铣刀的三维CAD模型以及加工立铣刀的砂轮刀位轨迹及NC代码,调用VERICUT软件进行立铣刀磨削加工仿真,从而保证立铣刀参数化设计的三维模型的可加工性,保证刀具设计的质量和缩短刀具设计和制造周期。     

Development of a novel variable rake angle mechanism for noncircular turning and its control

A prototype tool stage with a variable rake angle mechanism has been developed and controlled. The objective of the variable rake angle mechanism is to provide two-degrees-of-freedom to the conventional noncircular turning process, so that the rotational tool mechanism can compensate for the rake angle change caused by the noncircular cam profile itself while the translational tool motion generates the cam profile. Inverse kinematics, kinematic sensitivity and stiffness, and design of the variable rake angle mechanism are discussed. Robust repetitive controllers are designed for two actuators in the variable rake angle mechanism. Two actuators operate together to change the tool position as well as the tool angle. Experimental results on the variable rake angle mechanism support the design concept and control approach.     

Developing manufacturing response models to predict the manufacturability of new modular products

Product developers usually rely on their experience and knowledge during the design process to generate manufacturable products that can fulfill the required functions. Product developers make various decisions during the course of developing a modular product that affect the functional, physical, and operational structures, which either enhance or reduce the manufacturability of the products. This paper proposes constructing manufacturing response models by modeling the behavior of the manufacturability as a response to the series of decisions made during the design process. The manufacturability response models are mathematical models used to relate the product manufacturability to the different metrics used to quantify the results of the design decisions made during the development life cycle. Decisions made during the design process includes specifying the product functionalities needed to meet customer needs, the physical components capable of delivering the required functionalities, and the manufacturing processes needed to produce the physical components. Manufacturing response models can be used by product developers to predict the effect of the decisions made during the course of developing a modular product on the final modular product manufacturability. Furthermore, this paper demonstrates the construction of the manufacturing response models and their usage in new product design by using an illustrative example.     

螺杆压缩机转子型线设计方法

采用齿廓法线法,逐步演示螺杆压缩机转子型线的设计过程,并对复盛型线进行详细推导,验证了齿廓法线法在螺杆转子型线设计中的可靠便捷,从而得到了优于以往解析包络法的型线设计方法。