弧线齿逻辑齿轮设计

针对渐开线直齿圆柱齿轮传动存在的缺点,综合逻辑齿轮传动和弧线齿圆柱齿轮传动的各项优点,将逻辑齿廓应用于弧线齿圆柱齿轮,提出逻辑齿廓弧线齿齿轮设计。采用理论分析、数值计算相结合的研究方法对逻辑齿廓弧线齿齿轮进行设计。基于齿轮啮合原理和微分几何理论,首先建立了逻辑齿廓弧线齿圆柱齿轮的数学模型,然后利用MATLAB软件和CATIA软件实现了该齿轮的参数化建模,最后提出精确计算该齿轮的重合度的方法,并分析了齿宽和圆弧半径对重合度的影响,为大重合度弧线齿逻辑齿轮设计提供理论参考。     

平动齿轮机构连续传动条件的分析方法

平动齿轮机构中,过啮合点的齿廓公法线为动直线,故其啮合点轨迹不再是直线。本文采用求解两齿廓切点的方法探讨了该机构的齿廓啮合过程,在连续求解齿廓方程的基础上,可求出任一时刻同时参加啮合的轮齿对数,从而可判定传动是否连续进行,为平动齿轮机构的设计提供了理论依据。     

双圆弧弧齿锥齿轮重合度研究

重合度是影响弧齿锥齿轮传动啮合性能的主要因素。双圆弧弧齿锥齿轮的端面重合度为零,其连续传动由纵向重合度保证。根据弧齿锥齿轮重合度的定义,提出了双圆弧齿廓弧齿锥齿轮重合度的定义,并采用线图法对其啮合过程进行了分析;建立了双圆弧齿廓弧齿锥齿轮重合度、多点啮合系数和多齿对接触系数等计算方法,给出了双圆弧弧齿锥齿轮连续传动的条件。应用提出的方法对试验齿轮的重合度进行了理论计算,计算结果与TCA分析结果相同,验证了所提出方法的正确性。     

S型齿廓曲线齿轮的重合度研究

重合度是影响齿轮传动啮合性能的主要因素,是判断齿轮传动连续性及传递载荷均匀性的关键指标。S型齿廓曲线齿轮是基于提高齿轮接触强度而提出的一种新型齿廓曲线齿轮,为进一步探究其啮合性能,推导了S型齿廓曲线齿轮传动的重合度计算公式,讨论了S型齿廓曲线齿轮的重合度随齿数、模数、分度圆压力角及衍生系数之间的变化规律,并与相同基本设计参数下的渐开线少齿数齿轮作了对比分析。结果表明,S型齿廓曲线齿轮的重合度较同参数的渐开线齿轮有较大优势。     

圆弧针齿行星传动的重合度与齿面润滑系数

圆弧针齿行星传动机构是在长幅摆线针齿行星传动机构的基础上发展起来的一种新型传动机构。目前国内已有厂家在推广使用。当这种机构的传动比较小时,齿轮传动的重合度也是较小的。尽量增大这种机构的重合度是设计中的关键问题之一。本文提出了确定重合度的计算公式,分析了零件加工误差对齿轮重合度的影响。齿面滑动系数是衡量齿廓磨损的重要标志,本文提出的齿面滑动系数公式,可供研究机械效率的有关人员参考。     

减变速一体化端面活齿传动原理及啮合效率分析

为实现大重合度和高承载能力的连续变速比传动,融合活齿机构与非圆齿轮特性,提出减变速一体化端面活齿传动机构。首先,根据端面活齿传动机构及非圆齿轮连续传动条件给出了减变速一体化活齿轮连续传动条件,主、从动盘真实齿廓方程;然后根据齿廓对机构进行了压力角与啮合效率等性能的分析,并讨论了活齿的最大个数及机构构型;最后以偏心圆激波齿线与椭圆齿轮传动比函数为例对机构进行了仿真分析,从而验证了理论的正确性。     

直线共轭内啮合齿轮传动的齿形参数研究

针对直线共轭内啮合齿轮副的特性,参照渐开线齿轮传动定义了直线齿廓外齿轮的基本参数,讨论了齿顶半角、压力角和最小齿数的关系,分析了直线齿廓上的压力角随齿高的变化规律,提出了直线共轭变位传动的概念。在此基础上,对齿廓上的啮合极限点进行了研究,计算了直线齿廓上可以参与啮合的线段长度。通过研究齿廓线段与对应啮合转角之间的关系,推导了重合度计算公式,保证在齿形参数设计时满足连续传动的要求。最后通过内啮合齿轮泵的工程实例,验证了直线共轭内啮合传动的齿形参数设计方法和齿轮副的啮合传动性能。     

天文望远镜传动直齿轮齿廓修形设计

采用高次幂、短修形方式设计望远镜传动直齿轮,既满足重合度要求,又可改善齿轮的静传动误差,还能消除齿顶刮行现象,避免应力集中。定义空载传动误差设计曲线为齿廓修形参数,根据虚拟加工过程,建立修形齿廓方程。采用轮齿接触分析理论,结合有限元法,计算了空载传动误差曲线、齿轮承载变形曲线以及静传动误差曲线、并计算了定载荷情况下,考虑齿距误差的齿廓修形方程。结合仿真算例,对比未修形齿轮与修形齿轮的静传动误差以及主动轮齿顶处的应力,表明修形效果明显。     

高重合度内啮合复合摆线齿轮传动设计与分析

重合度是衡量齿轮传动性能的重要指标,较高的重合度对于提高齿轮的承载能力和传动的平稳性具有重要意义。考虑到摆线齿形的优越性,提出一种具有高重合度的新型内啮合复合摆线齿轮副;根据内、外摆线无包心形成法与包心形成法之间的等效关系,阐明内、外齿轮齿顶与齿根之间的齿廓配合关系,给出使重合度最大化的圆弧啮合线位置及其数学描述;结合坐标变换和齿轮啮合原理,建立共轭齿廓的数学方程,并由已知的啮合线推出适用于任意齿廓形状的齿轮端面重合度的统一计算式,推算上述内啮合摆线齿轮副的最大重合度,分析影响重合度的相关因素,指出提高重合度的可能途径。据此,运用Solidworks软件实现了高重合度内啮合摆线齿轮副的参数化建模,结合具体实例与标准渐开线内齿轮副进行比较研究,并就同时参与啮合轮齿的对数情况进行有限元仿真分析和光弹试验测试。结果表明,所设计的内啮合摆线齿轮副具有很大的重合度,可以到达十几甚至更大,且仿真及实测结果与理论分析吻合,验证了该齿轮传动理论的正确性。     

偏心针齿摆线行星齿轮传动研究

提出了偏心针齿摆线行星齿轮传动机构.分析研究了该机构的传动原理和传动结构.推导出了传动比计算公式,建立了齿廓方程,给出了齿廓曲率半径计算公式和齿廓出现尖点的条件.偏心针齿摆线行星齿轮传动是一种新型齿轮传动机构,根据这种机构可设计出大传动比的减速器和齿轮减速链轮等其它传动元件.     

Reduction of Air-Grinding Time Using Collaboration of Dual Sensors

Air-grinding time is inevitable in the grinding process. Since the low feedrate during air grinding makes the process inefficient, air-grinding time should be reduced. This paper presents a technology for reducing air-grinding time in cylindrical plunge grinding operations. The main idea is to estimate a distance, NAP (nearest approaching point), between the workpiece surface and the position of the grinding wheel. After detecting the NAP using an ultrasonic sensor, a CNC controller adjusts the feedrate using the feedrate override function with the help of the AE signal that gives the CP (contact point) information. The experimental results show that an ultrasonic and an AE sensor are good enough for detecting the NAP and the CP, respectively, and the system reduces the conventional air-grinding time by two-thirds.     

空间凸轮廓面检测与误差评定新方法及实验研究

在对空间凸轮廓面检测与误差计算方法进行深入研究的基础上 ,首次提出了适合于任何空间凸轮廓面检测的接触点回归法 ,建立了数据处理的数学模型和误差评定方法 ,解决了空间凸轮廓面检测与误差计算的难题。通过实验验证了该理论的正确性和可行性     

A measurement method for contact angle based on Hough Transformation

A measurement method for contact angle based on Hough Transformation is put forward in this paper. It is proved reliable through a study on the drop shape of water on Teflon, polypropylene and stainless steel. The measurement method for contact angle is implemented in the following procedures, drop shape image graying, and threshold segmentation with OTSU method, edge detection by Roberts operator, and the line and circle detection by Hough Transformation. The water contact angles on the Teflon, polypropylene and stainless steel are obtained by calculation; they are 113.23°, 104.34° and 77.28° respectively. The noise experiment shows that the method works with high robustness.     

Simplified stiffness model for spherical rough contacts

Abstract

Obtaining a surface with negligible roughness is very expensive, time consuming and unnecessary. The influence of surface roughness on the contact stiffness is of great importance. The extra cost associated with unnecessary surface finish can be limited by eliminating the unnecessary machining operations beyond the required surface finish. In this article, a simplified solution is presented to calculate the stiffness of rough contact between the workpiece and spherical locator; also, the effect of surface roughness on the stiffness and deformation of rough spherical contact is studied for different applied loads to find an ‘economic roughness’ under machining forces.     

The influence of surface roughness in elliptical contacts

The influence of surface roughness on contact behaviour is of great importance in many tribological situations. In the last decade several methods to calculate the pressure distribution and the real contact area in contacts between rough surfaces have been described. A problem arising for slender elliptical contacts, such as between gear teeth, roller and raceway, cam and follower, etc., is that the size of the contact is much greater than the size of the asperities. Accordingly the number of contact nodes necessary for an accurate solution to the problem becomes excessively large. This paper describes a method to calculate the influence of three-dimensional surface roughness in contacts that are very long in one direction. The method is based on restricting the calculations to a subpart of the real contact area, while the rest of the contact is taken into account by mirroring techniques. The results show that the real contact area is very sensitive to the amplitude of the roughness, while the waviness is less important. An equation is suggested from which the real area can be calculated if the smooth case contact parameters and two roughness parameters are known.     

NC METHOD FOR GENERATION OF CONJUGATINGHYPOID GEARS BASED ON NC‘S FLEXIBILITY

It is known that manufacture of hypoid gears is difficult and complicated, the reason lies on the limitation of traditional mechanical machine tools. With the development of NC machine tools, there should be new ways of cutting this kind of gear. Therefore, an idea to generate gears with conjugating tooth surfaces is proposed, based on the "flexibility" characteristic of NC that means various motions, in a sense, can be performed arbitrarily on NC machine tools. Using this method, the direction of the contact path on tooth surfaces can be controlled, and also, theoretically, the generated tooth surfaces can transmit motion at specific transmission ratio curve.     

Tribological modeling: Application of fast Fourier transform

The fast Fourier transform (FFT) technique is becoming an important tool in tribological modeling because an FFT-based algorithm can be extremely accurate and efficient. However, certain subtle issues should be properly dealt with so that efficient and accurate FFT implementation can be achieved. This paper discusses the use of three typical convolutions, two convolution theorems, influence coefficients, and shape functions, as well as the influence of domain size. This paper also explores the applications of FFT to inverse problems and periodic contacts and summarizes available FFT-based algorithms for solving various contact problems.     

接触变形与点啮合共轭齿廓传动性能预控

本文采用ＢＡＸＴＥＲ方法首次根据空间啮合原理和弹性力学理论考虑齿廓点接触区变形,它着重说明收缩齿制螺旋齿轮副弹性失配点啮合的性能和齿接触迹的予控。     

网络法求解相啮合齿面接触迹线的研究

通过研究本文提出了一种以网络结点为基础,在齿面上的活动标架里,计算出齿轮处于不同啮合位置时的接触点,以求得接触迹线的新方法,同时可校核在接触点之外,两齿面是否相交干涉。由于以齿面网络结点的离散数据描述齿面,这种方法可用来研究有误差或产生变形的真实齿面的形状和接触迹线,以便进行齿面的接触分析。