差动轮系的传动比与自锁问题的研究

研究了差动轮系中功率比与传动比的关系 ,得出了利用有关传动比判定啮合功率流向的几个公式 ,推导了各种不同输入输出条件下差动轮系的传动比取值范围 ,建立了差动轮系的自锁条件。     

行星变速器分析的新方法

2K H型差动轮系是构成行星变速器的核心 ,本文提出一种新的分析方法。用这种基本周转轮系 3个基本构件之间的传动比关系式推导行星变速器各挡位的传动比计算公式 ,用基本构件之间的功率比关系式分析变速器中各基本构件的输入输出特征 ,绘出功率流向图并确定啮合功率的流向 ,最后用传动比法导出啮合效率计算公式。     

基于双阵元超声波接收阵列的风矢量测量

针对当前超声波测风仪测量精度不高及抑制噪声干扰能力不强的问题,提出了一种双阵元超声波接收阵列结构及基于该结构的风矢量测量方法.首先,设计了一种基于超声波测风原理的风速风向测量系统结构,该结构中包含一个超声波发射阵元和两个超声波接收阵元;然后,依据该系统结构给出了一种基于相关方法的超声波时延估计算法,根据超声波传输时间与...     

Directivity analysis of ultrasonic waves on surface defects using a visualization method

Ultrasonic testing uses the directivity of the ultrasonic wave, which propagates in one direction. The directivity is expressed as the relationship between the propagation direction and its sound pressure. The directivity of an ultrasonic wave is related to the choice of probe arrangement, testing sensitivity and scanning pitch, and correct measurement of defect size and location. This paper investigated the directivity of ultrasonic waves, which are scattered from a slit defect located in simulated butt weld joint using a visualization method. When the defect size was smaller than the wavelengths, clear directivity in the reflected wave was observed. When the ratio of defect size to wavelength is greater than 1.5, measured directivities almost agree with the theoretical directivity. The directivity of shear waves scattered from the slit defect varied according to probe direction (Far defect, Near defect). The angle of reflection wave became similar to angle of incidence as the height of excess metal in welded joint increased.     

Improving the quality of surface in polishing process with the magnetic abrasive powder polishing (MAPP) by use of ultrasonic oscillation of work-piece on a CNC table

In this research work, polishing inside, outside and over the cylindrical parts has been done by using a completely new and innovative method. The work-pieces have been placed on a two-axis Cartesian CNC Table for polishing operations. The Magnetic Rotary Head continuously changes its rotation direction from CW to CCW and CCW to CW and meanwhile the part begin to oscillate up-and-down under a High Frequency (20 kHz) conditions. The Frequency of changing direction From CW to CCW and CCW to CW is one of the important parameters in this method. This method is a kind of Ultrasonic Assisted Polishing (UAP) and novelty of this research work is combining this method with motion of work piece under CNC trajectory with continuously changing direction of Magnetic Rotary Head. Gap between Rotary Magnetic Polishing Head and the Work piece Surface can be controlled by a power transmission screw which operates in the direction of the vertical axis. Several experiments have proved high performance of this new proposed method in the process of polishing in short times.     

剃齿安装误差对传动特性的影响研究

针对剃齿安装误差导致剃齿加工平稳性和齿面精度降低的问题,基于剃齿加工原理建立了含安装误差的剃齿分析模型,构造新的坐标转换,推导了含安装误差引起的补偿位移量。定量研究了剃齿安装误差对传动特性的影响规律,获取剃齿加工的传动误差和传动比曲线。并应用有限元法验证了模型和理论的正确性,为提高剃齿加工质量和效率提供理论依据。结果表明:轴交角误差对传动特性的影响比中心距误差大,实际生产中可通过轴交角误差来调整机床更有效地控制安装误差所带来的影响;随着轴交角误差绝对值增大,传动误差向负方向偏移越明显表明轴交角误差引起了较大的接触变形。     

弧齿锥齿轮的高重合度设计

针对航空和汽车弧齿锥齿轮对强度、动态性能和可靠性的特殊要求，提出了高重合度弧齿锥齿轮的设计方法。这种设计是通过增加工作齿高和调整齿面啮合路径方向以及优化加工参数实现的。结合弧齿锥齿轮的实际工况，提出了在不同载荷和安装误差下，实际重合度的综合分析方法，达到了既提高重合度又控制齿面啮合质量的目的。     

三轴差动式管道机器人机械自适应驱动技术

为解决管道内轮式移动机器人通过弯管时的运动干涉问题,减小因滑动摩擦而引起的磨损,提高该类机器人的使用寿命,提出一种具有管道自适应能力的轮式管道机器人驱动技术——三轴差动驱动技术。通过对三轴差动式管道机器人过弯管时内部传动系统的运动关系和力矩传递关系的理论分析及内部功率流向的深入研究,建立三轴差速轮系的力矩传递关系的数学模型,推导传递效率的理论计算公式,并证明该驱动技术驱动效率高,功率体积比大。     

An ultrasonic stage for controlled spin of micro particles

In this work, we proposed and developed an ultrasonic stage which can make different kinds of micro particles spin at its center. The stage consists of a circular copper plate and two piezoelectric half-rings bonded onto the bottom surface of the copper plate. The two piezoelectric half-rings have the same size and property, but opposite polarization in the thickness direction. They form a ring concentric with the copper plate. The spin direction of micro particles can be reversed by changing the operating frequency of stage. The spin speed can be controlled by operating frequency and voltage of the stage, and it reaches 955 rpm for a single glass ball with 0.51 mm diameter. The spin of micro particles is caused by travelling waves around the center of the stage, and the travelling waves are generated by anti-symmetric flexible vibration of the stage, excited by the two piezoelectric half-rings.     

PLC在车载天线控制系统中的应用

应用可编程序控制器(PLC)与电机变频技术,提出了快速调整车载天线方向的构想与设计方法,研究了车载天线转动方向与PLC输出的驱动脉冲、传动减速比之间的关系,并提出了合理的减速比,使车载天线转动方向与脉冲串符合实际需求。综合运用PLC的传送、计算、比较等功能指令编程,控制变频器驱动脉冲的输出,可以保证车载天线准确变换方向,同时保持较高的定位精度。从目前国内相关技术应用情况来看,PLC在车载天线方向控制上的应用,能够充分发挥其系统配置灵活、安装操作简单、实现功能多等突出优点。     

复合行星齿轮传动系统虚拟样机仿真研究

根据Ravigneaux式复合行星齿轮传动系统的典型结构,分析了系统的传动比与啮合频率。为获得Ravigneaux式复合行星齿轮传动系统轮齿接触力的变化规律,运用三维CAD软件SolidWorks建立了系统的三维实体模型,以ADAMS软件为平台建立了系统的虚拟样机模型。给出基于Hertz接触理论的齿轮啮合传动时轮齿接触力的计算方法,验证了系统传动比,对小太阳轮与短行星轮啮合的综合接触力、x方向接触力和y方向接触力的变化规律及其频谱特性进行仿真研究。仿真结果表明,接触力的幅值波动显著,具有明显的周期性。x方向接触力和y方向接触力具有相同的频谱特征,相位相差约90°。频谱中出现小太阳轮的旋转频率和系统啮合频率的1至7倍频率成分,存在明显的调制特性。通过对Ravigneaux式复合行星齿轮传动系统虚拟样机仿真的研究,为改善系统动力学特性以及实现系统的动态设计提供了指导依据。     

摇摆工况下电动汽车高速斜齿轮传动振动控制方法

在摇摆工况下,当无级变速转换为传动变速时,导致扭矩方向及大小的偏移、主转速和从转速不一致,从而产生斜齿轮传动振动问题,为此,提出了基于线性反馈的电动汽车高速斜齿轮传动振动控制方法。通过分析斜齿轮传动时内部的电流走向,明确传动装置的速度比与金属带速度比的反比关系。结合动力学和傅里叶变换算法,推导出速度导纳、位移导纳以及加速度导纳间响应关系,利用响应系数识别 3 种导纳情况下,传动原点处的共振与反共振参数,以此为基础,采用线性反馈混沌控制法建立反馈数据增益矩阵,得出具有稳定周期的调节系数,利用调节系数控制传动点的运行轨迹,完成传动振动的高效控制。仿真测试结果表明,该方法提高了汽车内部共振区域频率波动的吻合程度,有效降低了外界噪声及其他干扰因素导致的传动振动影响,控制性能较好。     

轿车用自动变速箱的发展动态

随着对换档品质。燃油经济性等方面要求的不断提高,自动变速箱在轿车上的装车率也提高。目前自动变速箱的主流形式是流力机械式。最新的发展方向集中在以下几方面,变矩器的高效率化、多档位化、变矩器没离合器的打滑控制、换档点控制的智能化、换档过渡过程的高品质化和保留手动模式。本文详细讨论了上述各项技术的发展背景、核心技术和发展方向等问题。     

用运动学法进行有误差斜齿轮传动的空间啮合分析

在斜齿轮实际啮合中,由于误差的存在,齿轮的啮合已不同于理论啮合分析。本文用运动学法进行了有误差斜齿轮的空间啮合分析。通过给定方程,可用计算机模拟计算其瞬态啮合特性：①齿轮瞬时接触线（或点）和瞬时接触法线方向;②齿轮瞬时传动比和齿轮综合传动误差。     

Increasing the signal-to-noise ratio in ultrasonic testing of repair welds using the technology of thinned antenna arrays

To test objects of materials with a high level of structural noise, use of thinned antenna arrays (TAAs) that have a large spatial aperture and consist of a small number of elements that are positioned from one another at a distance larger than the wavelength is proposed. A TAA moves over the surface of a tested object and echo signals are recorded during transmission and reception by different pairs of piezoelectric plates. For each transmitter-receiver pair, the measured echo signals are used to reconstruct partial images, which are then coherently added together to form the final image, by the SAFT method. A procedure for calibrating each piezoelectric plate of the TAA in order to determine the coordinates of its center for efficient coherent summation of partial images has been developed. The calibration procedure reduces the requirements for the accuracy of the arrangement of the piezoelectric plates of the TAA on a prism. The use of the technology of TAAs allows one to obtain images of flaws in repair welds with a signal-to-noise ratio (SNR) that is 12 dB higher than the SNR for an image obtained using the technique for a single-element transducer. The results of testing specimens of 800 pipelines with repair welds in weld seams are presented. The efficiency of this method is shown in comparison to the method in which a single-element piezoelectric transducer is used.     

电液伺服泵控系统柔性传动比理论研究

电液伺服泵控系统具有高效节能、高功重比和环境友好等技术优点,但受诸多非线性因素的影响,系统传动特性表现出极强的非线性。通过深入研究电液伺服泵控系统的传动特性,提出柔性传动比理论,建立电液伺服泵控系统的数学模型,得到伺服电机-定量泵-液压缸之间的柔性传动比规律。对柔性传动比应用进行研究,提出基于广义排量的压力控制策略。搭建系统柔性传动比仿真与试验平台,对柔性传动比理论应用进行仿真和试验研究。研究结果表明,柔性传动比理论的应用对压力控制具有良好的控制效果,将为电液伺服泵控系统的工程推广与应用奠定良好的基础。     

High precision ultrasonic guided wave technique for inspection of power transmission line

Due to the merits of high inspection speed and long detecting distance, Ultrasonic Guided Wave(UGW) method has been commonly applied to the on-line maintenance of power transmission line. However, the guided wave propagation in this structure is very complicated, leading to the unfavorable defect localization accuracy. Aiming at this situation, a high precision UGW technique for inspection of local surface defect in power transmission line is proposed. The technique is realized by adopting a novel segmental piezoelectric ring transducer and transducer mounting scheme, combining with the comprehensive characterization of wave propagation and circumferential defect positioning with multiple piezoelectric elements. Firstly, the propagation path of guided waves in the multi-wires of transmission line under the proposed technique condition is investigated experimentally. Next, the wave velocities are calculated by dispersion curves and experiment test respectively, and from comparing of the two results, the guided wave mode propagated in transmission line is confirmed to be F(1,1) mode. Finally, the axial and circumferential positioning of local defective wires in transmission line are both achieved, by using multiple piezoelectric elements to surround the stands and send elastic waves into every single wire. The proposed research can play a role of guiding the development of highly effective UGW method and detecting system for multi-wire transmission line.     

类四杆五杆机构连杆曲线的变化规律

类四杆五杆机构连杆曲线的变化规律张旭滨（渤海铝业有限公司０６６０００）贲宏艳刘葆旗（燕山大学）１引言类四杆五杆机构就是把铰链四杆机构的某一个杆ａ截成两个杆，并用转动副相联，较短的一个杆称为调节杆ｅ，较长杆为ａ′，且ｅ／ａ′≤０．２５，ｅ和ａ′的传动...     

除臭处理下的生活垃圾气力输送系统多模块化设计

为了确定最佳气力输送比,以极高的功率完成垃圾输送,减少运行成本,提出了除臭处理下的生活垃圾气力输送多模块化系统.在保证电路安全稳定的基础上,减小了电路电压,设计了生活垃圾投放运输模块、生活垃圾除臭处理模块和生活垃圾处理回收模块,通过具体的管道方向,选择了最适合的气体表达传送方式,且尽量将气力输送比调整为最佳区间,将除臭工序重复 ３~４ 次,并有效识别了生活垃圾中的气体、液体和固体,完成除臭处理下的生活垃圾气力输送系统多模块化设计.实验结果表明,所设计系统的平均成本为 ２４３．９ 元,其运行成本明显低于对照组,减少了系统运行的成本.     

回流式无级变速器动力连续转换的控制策略仿真研究

为避免回流式无级变速器在无级与回流工况转换过程中动力中断,以减小对整车冲击度的影响,提出了回流式无级变速器动力连续转换的控制策略。针对转换过程中变速器效率和金属带功率流方向变化对输出转矩的影响,建立了转换过程中离合器接合、分离的动力学模型,确定了离合器扭矩变化率的限定范围。利用MATLAB/Simulink仿真平台,对回流-无级和无级-回流转换过程进行了仿真研究,结果表明:采用回流式无级变速器动力连续转换的控制策略,冲击度控制在5m/s3以内。