一种斜楔机夹镗刀

烟台市技术学院实习工厂生产多种型号出口美国的变速器，属大批量生产。为了达到客户必须保证产品低噪音的质量要求，对变速器壳体中的轴承孔形状、位置精度要求较高。变速器壳体材料为QT400—15的铸坯件，其轴承孔均为有加工余量的铸孔，内表面粗糙，硬度高。由于不同型号铸孔的内径、轴向尺寸均不相同，需要制造多种规格的镗刀。我们曾使用单刃镗刀、焊接组合镗刀、外机夹镗刀进行加工，均不理想。为此，我们设计制造出了新颖、实用的内置斜楔机械夹紧镗刀。     

飞机交点孔超声椭圆振动精密加工技术

针对常规方法加工30mm以上的飞机翼身交点孔存在动力不足、孔径精度差和表面质量不高等问题,采用超声椭圆振动镗削的方法,研制了超声椭圆振动镗削装置,并对30mm以上不同材料的翼身交点孔进行了镗削加工,取得了很好的工艺效果,充分体现了超声椭圆振动镗削技术在飞机交点孔加工中的优势。     

液力传动箱精镗模

北京型内燃机车液力传动装置的传动箱加工精度要求比较高,各主轴孔均为一级精度,表面光洁度6,各主轴孔同轴度公差≯0.05毫米,各主轴孔中心对二轴孔中心线平行度公差≯0.05毫米。过去我们在镗床上加工,既烦琐、劳动强度大,又很难保证加工精度。为此,我们设计制造了一台传动箱精镗模。传动箱精镗模由动力部分、镗模部分、输送镗杆部分、镗杆部分、液压部分和电气部分组成。     

在车床上加工汽车过桥箱盖上的Ф130K6孔

我厂生产的99014320124过桥箱盖(见图1)是双后桥重载汽车上的重要零件之一。过去在TH6363卧式加工中心或镗床上加工该过桥箱盖上的130K6孔,生产效率很低,每天只能加工20多件,不能满足集团公司每月装配1000套车的需要。为了解决这一问题,经过反复试验,我们在车床上加工过桥箱盖130K6孔获得成功。1车床上镗削130K6孔的关键技术要求(1)必须使130K6孔的中心线与车床主轴中心线同轴(要求◎0·004mm),要满足这个要求,车床加工工件的回转直径必须大于630mm(见图1);图1(2)加工时工件迅速、正确定位,以保证所需加工精度;(3)要保证零件…     

大深径比微小深孔超声电火花加工工艺研究

针对难加工材料的大深径比微小深孔加工这一工艺难题,设计并制造了基于工件振动的超声电火花复合加工装置。该装置包括一个已优化的压电振子和一台普通电火花机床。为提高加工效率,对压电振子进行了优化分析,使压电振子具有合适的纵振模态、固有频率和较大的振幅,压电振子中陶瓷片具有合理地安装位置。选择模具钢作为加工材料进行大深径比微小深孔的加工实验,比较研究了超声电火花复合加工装置和普通电火花机床加工大深径比微小深孔的加工效率。实验表明,超声电火花复合加工装置的加工效率更高。研究了超声激励电压、脉冲电流、脉冲宽度以及脉冲间隙等参数对大深径比微小深孔加工效率的影响,得出各参数较优的设置值。根据实验结果可以看出,超声电火花复合加工装置可以有效地加工出直径为0.5mm、深径比为60的微小深孔,适用于难加工材料的大深径比微小深孔加工。     

高精度箱体主轴孔的镗削

在高精度箱体主轴孔的镗削中,镗模的导向支承采用液体动压轴承。它具有间隙小、回转精度高、耐磨性好等优点,能显著改善箱体主轴孔的加工质量,特别适宜于高精度箱体主轴孔的镗削。镗模结构图1是CG6125车床箱体主轴孔的加工图。镗模安装在专用镗床工作台上,工件以已加工的M、N面定位,安装在镗模的基准板上(如图2所示),使工件上待加工孔与镗模板上的孔同轴。镗杆则安装在镗模板上的前后镗套内,这样可大大提高机床-夹具-刀具-工件间的刚性。镗杆与机床主轴采用精密活动接头联接(如图3所示),以减小机床误差对工件精度的影响。整套镗模的结构较简单,由定位基准板、调整块、镗模板及镗杆组成。定位基准板的M、N面,必须根据床身安装主轴箱的技术要求来制造,并要有一定的精度储备量,这样加工的工件就具有较好的互换性。     

气缸体缸孔精镗刀架及镗刀的改进

2009年,我公司引进两台大连产气缸体缸孔精镗床,主要用于承担L系列所有型号柴油机气缸体止口孔、缸孔精镗及缸孔孔口倒角关键工序加工。前期小批试切过程中,常出现刀架碎裂、镗刀磨损过快等异常现象,导致气缸体缸孔加工质量不易保证,并且部分柴油机气缸体不能兼顾生产,设备利用率低下。1.存在问题通过系统分析发现,原设备所带止口孔、缸孔刀架、镗刀主要存在以下几方面问题：（1）原缸孔精镗刀总成如图1所示,     

专用镗杆

为了修复C616车床床头箱主轴孔,我们制造了一套如图所示的专用镗杆,使用时将车床主轴及末端的内接齿轮取下,把前主轴承换成6213轴承,装上这套镗杆,即可利用车床本身的传动对主轴箱进行镗孔。采用这种方法,修理一台车床、从拆卸、加工到试车,仅用一班时间,质     

高效精密镗孔技术

大型船用柴油机机座主轴承精密镗孔,历来是一项难度较高、耗时很多的加工项目。为此,我们作了一系列的分析和探索,取得了较为满意的效果。一、大型零件内孔精镗的主要矛盾最近制造的一台国内最大7RT8柴油机,其机座主轴承孔径为970mm,实际镗孔总长为3145mm。对于这类大型内孔的精密镗削,主要有下述三点困难。 (1)孔壁厚度各处不一,因而热变形量大小也不同,这就极易造成各处实际切除的余量并不相同。所     

缸孔精镗工艺的优化

发动机缸孔的加工是缸体加工中的关键环节,精镗为其中的中心环节,其加工节拍长、加工内容多、加工质量要求严格。以某发动机缸体生产线缸孔加工中精镗工艺为例,结合实际生产中遇到的问题,就缸孔精镗加工工艺的优化进行浅要的解析。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...