首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
螺纹联接防松方法的评述   总被引:3,自引:0,他引:3  
项忠霞  董刚 《机械设计》1996,13(11):1-2,32
本文分析了紧固螺纹联接松动的原因,对常用的多种防松型式进行了性能比较,指出了螺纹防松装置的设计要点是设法阻止紧固螺纹副之间的相对转动,最后对几种新的防松型式做了简要的介绍。  相似文献   

2.
螺纹联接的防松方法   总被引:1,自引:0,他引:1  
螺纹联接的松动问题一直困扰工程界和学术界。从原理上分析了螺纹联接松动的原因,介绍了一些目前常用的防松方法,着重介绍了几种新型防松方法。  相似文献   

3.
螺纹联接具有联接牢固、装拆方便、易于标准化等优点而得到极为广泛的应用。但是简单的螺纹联接不能有效地防松。为了防止螺纹联接的松动,产生了很多防松的办法。如采用双螺母紧固、防松弹性垫圈、防松销钉、涂抹螺纹粘接剂等。但是这些方法仍然不够理想,有的防松效果不佳、有的结构过于复杂、有的不利于重复拆卸。本文介绍的自锁螺纹是一种既具有理想防松效果、而结构又非常简单的螺纹联接系统。  相似文献   

4.
本文讨论了螺纹联接的自动松动机理和防松方法。其自动松动的主要原因有三个方面:当螺栓受横向力反复作用后,螺栓体产生弹性扭转;当螺栓联接受到轴向变载荷或在冲击振动载荷作用下,也会使螺纹副和载荷支承面间产生较大的相对滑动速度,导致摩擦力逐渐减小,甚至瞬时消失,而引起螺纹联接的自动松脱;此外,螺纹联接体的初始变形对自动松动的影响也不可忽视。研究表明,当螺栓的紧固力矩T_f小于螺纹联接的临界反作用力矩T_(cr)时,螺纹就会发生自动松动。为了墙加螺纹联接工作的可靠性,必须考虑其防松方法,本文既评述了传统的防松方法,也介绍了一些新的防松措施。  相似文献   

5.
重点分析螺纹联接的松动机理,把松动过程分为两个阶段,第一阶段是因螺纹根部材料的局部塑性变型造成预紧力下降的过程,第二阶段是由啮合螺纹间的微滑移和接触压力的变化引起螺母旋转后退的过程。为了更好地设计和选择防松方法,分析预紧力和预紧力矩之间的关系,探讨预紧力、摩擦力、螺纹磨损等因素对防松性能的影响。从抑制螺纹副的相对运动出发,分析国内外先进的防松方法。以横向振动试验结果为依据评估一些防松方法的性能优劣。该文为螺纹联接防松方法的设计与选用提供指导。  相似文献   

6.
浅谈螺纹锁固胶的选型与应用   总被引:1,自引:0,他引:1  
螺纹联接是一种可拆卸的固定联接,具有结构简单、联接可靠、拆装方便等优点。螺纹联接包含拧紧技术与防松技术,螺纹联接防松的方法很多,如机械防松、摩擦防松、螺纹锁固胶防松等,其中,螺纹锁固胶防松技术具有高效、便捷、可靠、成本低等特点,已在机械行业得到广泛的应用。重点阐述了在众多螺纹锁固胶产品的背景下,企业如何正确地选型与应用螺纹锁固胶。  相似文献   

7.
在工程上,螺纹联接的防松是十分重要的。因为,螺纹联接一旦出现松脱,轻者影响机器的正常运转;重者造成严重事故。因此,为了防止联接松脱,在设计时总是根据具体情况,认真选用行之有效的防松措施。在众多的防松措施中,同旋向双螺母锁紧防松(或称对顶螺母防松)是一种结构较为简单、应用极为广泛的防松措施(图1)。它是利用两个螺母的对顶作用使螺纹副中始终存在足够大的压力和摩擦力,以阻止螺纹副出现相对转动,达到防松。但是,在具体使用中发现此方法不仅装拆螺纹联接件非常费力,而  相似文献   

8.
螺纹联接中常见的摩擦防松,在变载荷、振动冲击、高温或温度变化较大的场合,可能会导致联接失效。常见机械防松装置虽防松可靠,但不可拆卸或不易反复装配,也不利于自动化装配作业。为保证在特殊环境下,螺纹联接防松可靠,拆卸方便,并有利于自动化装配作业,设计有效的螺纹联接型式,采取有效手段,提高防松能力是工程实践中应重视的问题。  相似文献   

9.
螺纹联接的松脱机理及其防松措施   总被引:1,自引:0,他引:1  
螺纹联接作为一种联接技术已经广泛运用于机械工程中,它具有结构简单、联接可靠、装卸方便等优点,在机械中应用广泛。特别是其具有的自锁性在静载荷下不会自行松脱,但在冲击、振动或交变载荷作用下,会使螺纹牙之间的正压力突然减小,导致摩擦力矩减小,螺母回转,使螺纹联接松动。本文就螺纹联接的松脱机理进行探讨并提出螺纹联接的防松措施。  相似文献   

10.
巩浩  刘检华  冯慧华 《机械工程学报》2022,(10):326-347+360
螺纹松动失效将导致螺纹连接失去原有的功能、降低机械产品性能,甚至在某些情况下诱发紧固件疲劳断裂,进而引发严重的安全事故。国内外学者针对螺纹连接的松动机理和防松方法展开大量的研究,为充分了解松动机理和防松方法的研究进展,推动相关问题的深入研究,在阐述螺纹连接松动内涵的基础上,提出将螺纹连接松动分为非旋转松动和旋转松动两个类型,并从非旋转松动和旋转松动两个方面对螺纹连接松动的相关研究进展进行综述;同时从传统防松结构和新型防松结构两个方面,对螺纹连接防松方法的相关研究进展进行综述。最后,对论文进行总结,并展望了螺纹连接松动机理和防松方法的未来研究方向。  相似文献   

11.
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...  相似文献   

12.
The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...  相似文献   

13.
黑棣  郑美茹 《机电工程》2016,(11):1315-1321
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。  相似文献   

14.
The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.  相似文献   

15.
The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...  相似文献   

16.
The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....  相似文献   

17.
马立新  王宏宇 《机电工程》2015,32(1):118-122
针对传统的电力系统多目标粒子群优化算法采用权重系数法将多目标转化为单目标,从而忽视了各目标函数间的竞争关系这一问题,提出将非支配解提取法运用到电力系统多目标无功优化中,并设定了一套提取规则,以电力系统中的有功网损、电压偏差和电压稳定裕度为目标,使目标在充分竞争的情况下得出Pareto最优解,利用IEEE-14节点系统对多目标非支配解提取法的电力系统无功优化进行了仿真测试。研究结果表明,该算法一次运行可以得出多组非支配解,既有偏向单个目标的解也有兼顾所有目标的解,克服了权重系数法的盲目性和单一性,可使电力决策者根据实际问题选择最优解,具有较好的灵活性与多样性。  相似文献   

18.
A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.  相似文献   

19.
This article describes designing, implementation and tuning processes of multiple-tapped-delay-line (MTDL). Obtained MTDL can be implemented in various field-programmable-logic-devices (FPGA) devices and applied for time-to-digital-converters (TDC) construction. The task of tuning process is the tapped-delay-line (TDL) linearisation, and consists of two stages. The first stage depends on selecting an appropriate configurable-logic-block (CLB) for particular delay-segment realization and selecting proper connection between these blocks. The second tuning stage, that is essential from this article viewpoint, depends on inter CLBs connecting wires delay regulation realized directly by load regulation. The Load regulation depends on connecting an appropriate number of unused three-state-buffers or CLB inputs to the wire which delay is adjusted. Depending on the number of inputs connected to the wire its capacitance changes that influences its time-constant and finally changes its time-delay.The MTDL mathematical model, obtained characteristics and results of time-interval (TI) measurements are also presented. The derived TDL model provides information about how the particular wire delay should be changed and in which order the changes should be executed. This makes the designing process predictable and easy to carry out. Presented characteristics confirm the proper operation of presented linearisation technique. The proper operation of the whole measuring module is confirmed by obtained TIs histograms presentation.  相似文献   

20.
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。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号