铸造起重机小车减速器振动原因分析

针对铸造起重机小车减速器的振动现象,采用有限元分析,找出了导致其振动的真实原因,为起重机小车的布置及结构设计提供了技术依据,对提高起重机的质量和安全性具有重要意义.     

棘轮棘爪减速器在铸造起重机中的应用

分析了用于铸造起重机的常规减速器的不足之处,阐述了棘轮棘爪减速器的工作原理及其优点.介绍了棘轮棘爪减速器应用于铸造起重机的效果.     

大型铸造起重机选型及安全维护策略探讨

大型铸造起重机按照起重机主梁结构划分,主要有四梁四轨型式和四梁六轨型式两种型式;按照主起升机构的结构划分,可以分为整体减速器和行星差动三减速器结构型式.介绍了两种主梁结构铸造起重机的型式及主起升机构减速器的特点,明确主起升机构关键部件的维护方式以保证大型铸造起重机的安全运行,同时对大型铸造起重机的结构、主起升机构以及安全装置的选型提出建议.     

铸造吊小车架一体化减速器有限元分析

由于厂房对起重机的净空极限要求,为减小起重机整体高度,将起升减速器的大齿轮沉入小车架的减速器梁内,同时为增加小车架与减速器箱体的刚性,减速器下箱体与小车架一体焊接成型。小车架一体化的连接方式也带来了新的问题,减速器箱体的变形不仅受轴承支反力的影响,还受小车架整体下挠的影响,设计时需要综合考虑。采用有限元方法对小车架一体化减速器箱体应力和变形状态进行分析,验证设计的可靠性。     

铸造起重机升级改造中平衡架的有限元分析

运用数值分析手段,基于有限元软件建立了铸造起重机升级改造中平衡架的数值模型,在铸造起重机吊重工况条件下,分析得到了平衡架的应力及变形特征,验证了平衡架的强度、刚度满足设计安全要求,并根据数值分析结果对应部件提出了合理化建议,为其结构的改进和优化提供了一定参考依据。     

取料机行星减速器齿轮架断裂失效分析

首先采用经典力学分析方法,获取行星减速器典型工况的载荷条件,同时利用有限元数值分析方法对减速器进行三维实体有限元分析,利用理论分析发现行星轮支撑架与行星架转动轴的结构中存在不合理的原始设计缺陷与加工缺陷.改进后行星减速器的工作可靠性通过实际使用发现有明显的提高.通过本次分析获得了一种分析减速器零件过早失效的科学方法,研究结果为该减速器后期的安全使用提供了较好的理论支持.     

125/32起重机(A6)特护的理论依据及实施效果

对邢钢混铁炉跨125／32吨桥式铸造起重机的使用情况，按照国家标准进行了分析和计算，对该起重机的现状作了定性的分析，预测了该起重机的预期使用寿命，提出末期维护的措施。为公司决策和现场使用提供理论根据。     

铸造起重机起升机构典型方案比较及棘轮机构的应用

通过对起重机起升机构两种典型方案进行比较,推荐了240 t以下铸造起重机的优选方案,并结合控制过程分析,阐述了棘轮机构在双减速器低速轴刚性连接方案中的应用优势:在使用刚性连接方式满足机构冗余设计的同时,解决了两套驱动机构功率流的柔性匹配,避免了设备运行时有害内应力的产生。     

某165t铸造起重机桥架开裂的分析研究

以165 t铸造起重机原始参数为基础,对开裂桥架进行了理论计算和有限元分析,得到不利工况下的应力结果,结合理论和有限元分析结果,桥架的强度及疲劳寿命均满足设计要求,大车运行轨道安装超差,运行不平整,冲击载荷大,超载运行等原因造成桥架的开裂。     

子模型技术在铸造起重机强度分析中的应用

提出了一种预测大型起重机结构疲劳寿命的方法。通过采用三维有限元 (FEM)和子模型技术对某炼钢厂一台铸造起重机进行了强度分析 ,计算所得到的焊缝强度最薄弱环节与实际情况吻合。在现场动态测试基础上 ,运用Miner公式并结合修正后的p-s-N曲线及实际载荷谱 ,计算得到了该起重机主梁的疲劳寿命。     

论从实践理解世界的物质性和自然世界的先在性

马克思主义唯物论是一种物本主义形态的唯物论,还是一种超越物本主义形态、从实践理解世界的本质相关问题的实践的唯物主义的唯物论?这是一个我们必须搞清楚的有关马克思主义唯物论的本质规定性和精神实质的重大问题.在考察物本主义的唯物论及其思维方式的局限性的基础上,揭示了马克思主义唯物论是现代的、实践的唯物主义,并重点研讨了马克思主义唯物论关于从实践理解世界的物质性和自然世界的先在性的原理,以期为马克思主义唯物论进一步阐明人类世界的实践性原理奠定基础.     

Effect of cyproheptadine on the ultrastructure of the neurons of the arcuate nucleus in the hypothalamus of the rat

The data are presented on changes in the rat arcuate nuclear neuron ultrastructure after using cyproheptadine (peritol, Egyt Pharmaceutical Works, Hungary) in a water suspension at a dose of 20 mg/kg once daily during 7 successive days and twice a day within 10 days. It was shown that cyproheptadine decreases the functional activity of the arcuate nuclear neurons, depending on the total amount of the drug used. Cyproheptadine-induced inhibition of the forming neurohormone release from neurons is likely to be one of the mechanisms of its therapeutic effect in Itsenko-Cushing's disease.     

Characteristics of the sympathetic innervation of the nictitating membrane and of the vasculature of the nose and tongue of the cat

Vasomotor responses from the nasal mucosa and tongue, and contractions of the nictitating membrane, were recorded on stimulation of the cervical sympathetic or internal carotid nerves. Preganglionic sympathetic nerve fibres which elicited a membrane response possessed a lower threshold than those which evoked nasal vasoconstriction, while the latter displayed a lower threshold than fibres which evoked tongue vasoconstriction. The sympathetic vasodilator fibres to the tongue whose activity was revealed after alpha-receptor blockade, had a similar threshold to the vasoconstrictor fibres. Membrane contraction, nasal vasoconstriction and occasionally tongue vasoconstriction could be evoked by stimulating the internal carotid nerve. The postganglionic fibres innervating the nasal mucosa had a similar threshold to those of the nictitating membrane, which may indicate that there are small myelinated fibres innervating the mucosa. The preganglionic compound nerve action potential had four major components, S1-S4. S1, S2 and usually S3 fibres were associated with membrane contraction; S2, S3 and sometimes S1 fibres were associated with nasal vasoconstriction; and S3, usually S2 and occasionally S1 fibres were associated with vasoconstriction in the tongue. It is concluded that each of these three groups of nerve fibres, but not S4 fibres, may include fibres associated functionally with the three effectors. There was a considerable difference between the relative amplitude of the responses of the three effectors elicited by stimulation of the cervical sympathetic nerve at frequencies between 0.2 and 2 Hz. Vasoconstrictor responses were relatively larger than membrane contractions suggesting differences in the mechanisms of neurotransmission at the neuroeffector junctions.