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大型锻压机床进行压力加工时,锤锻频率的提高有利于锻件质量的提高,但会引起卸压冲击。通过分析卸压过程引起冲击的原因,建立了泄流流量与动量变化间的关系,得出了快速无冲击卸压时泄流口面积与时间的关系,可为合理设计泄压口提供依据。 相似文献
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该文分别对节流、比例阀、三级组合逻辑阀卸压的技术进行了比较分析,提出了在高压、超大流量液压系统的油缸、管道、泵口等压力能集聚区采用基于PLC控制的小流量多点快速卸压技术,有效地解决了使用工况恶劣、油液易污染的情况下大型锻造液压机在回程换向时的液压冲击,缩短了换向时间,提高了工作频次。 相似文献
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重型油压机进入保压状态后或回程前,油缸和机架系统会储存很大一部分能量.为解决油压机回程状态下液体压力所产生的冲击而带来的油压机和液体管道振动问题,设计了一种低速卸压装置,对卸压过程中的能量进行了分析计算,得出了系统储能与泵流量呈非线性关系的结论.借助有限元分析软件ANSYS Workbench对低速卸压装置结构进行了拓扑优化,在保证其刚度和强度的前提下,使其质量有所降低. 相似文献
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《液压与气动》2020,(10)
工程上经常使用液压缸对大型球阀进行开关操作,并在开关位置设计机械限位机构,要求液压缸在开关位具备锁紧功能。传统锁紧回路在锁紧后,高压腔压力始终维持在系统设定的较高压力,往往造成限位机构损坏。从液控原理上分析了常用液压锁紧回路的特点,在此基础上提出了一种可降卸压双向液压锁紧回路,详细介绍了这种锁紧回路的原理和特点,为验证该回路具备可快速卸压至预设定压力的功能,使用液压仿真软件对传统锁紧回路和可降卸压双向液压锁紧回路进行了仿真,对比分析了执行液压缸高压腔的压力变化情况。分析表明,可降卸压双向液压锁紧回路在锁紧后可执行液压缸高压腔迅速降低到预设压力,具备有效保护执行机构的功能,满足实际工程需要、安全可靠,为安全、精确控制液压执行元件提供了一种新的液压控制方案,其设计过程和分析方法对拓展液压锁紧回路在工程实践上的应用具有一定的参考价值和指导意义。 相似文献
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基于高压超高压压力控制技术在小容腔上的应用,利用高压超高压控制分析方法建立了小容腔的高压超高压增压系统。通过推导小容腔压力容积变化关系建立了数学模型。根据小容腔的数学模型设计了压力控制系统。系统采用两级气驱液体泵对小容腔进行增压,容腔压力可达到150 M P a。控制系统采用工业控制计算机和P LC共同完成,能够达到任意设定的压力值,并能够自动保持压力,压力控制精度可达0.5%FS。 相似文献
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二维(2D)阀的阀芯具有周向转动和轴向移动的2个自由度,可实现先导控制和功率放大。其先导级阀口因节流会产生气穴,引起阀芯振动并伴有噪声,直接影响阀的稳定性。为研究2D阀先导级处气穴现象及其影响因素,开发了一套可视化实验装置,结合两相流仿真研究,验证了气穴现象与阀口开度、敏感腔体积、节流口形状、入口压力关系密切。结果表明:2D阀先导级高压节流口处的气体体积随阀口开度的增加而减少,直至消失;随入口压力增加,气体体积的变化近似呈线性增长趋势;随着敏感腔体积的增大而显著增加,平均增长速度达62%,且气体分布变得不规则;矩形节流口比弓形节流口处的气穴受入口压力等因素的影响较大,弓形节流口在入口压力增加时,气体体积增量仅为矩形的8%;同时发现,随着气体在感受通道内的扩散,气体边界从最初的类矩形变成多段不规则形状。 相似文献
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基于AMEsim与ADAMS的双钢轮压路机振动液压系统的仿真分析 总被引:2,自引:0,他引:2
双钢轮振动压路机压实作业时需要频繁起振和停振,起振和停振过程中路面质量难以保证,所以要求起振和停振的动态过程能在较短的时间内完成.振动系统是1个大惯量系统,由于机器状态改变会带来很大的惯性力,这势必造成液压系统的压力冲击,过大的液压冲击会影响液压元件的寿命和机器的可靠性.利用AMEsim和ADAMS软件对该液压系统和振动偏心轴构成的机械系统进行仿真,研究了系统的动态过程和压力冲击控制方法. 相似文献
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Denghao Wu Yun Ren Jiegang Mou Yunqing Gu 《Journal of Mechanical Science and Technology》2017,31(5):2155-2166
Circulator pumps have wide engineering applications but the acoustics, vibration and unsteady flow structures of the circulator pump are still not fully understood. We investigated the noise and vibration characteristics and unsteady flow structures in a circulator pump at different flow rates. Three-dimensional, unsteady RANS equations were solved on high-quality structured meshes with SST k-ω turbulence model numerically. Measurements were made in a semi-anechoic chamber to get an overview of noise and vibration level of a pump at different flow rates. The 1/3 octave-band filter technique was applied to obtain the explicit frequency spectra of sound, pressure fluctuations and vibration signals and their principal frequencies were identified successfully. The air-borne noise level of the designed condition is lower than that of the off-design conditions, and the highest sound pressure level is found at part-load condition. The acoustic emission from the pump is mainly caused by unsteady flow structures and pressure fluctuations. In addition, both the link between airborne noise and pressure fluctuation, and the correlation between vibration and unsteady hydrodynamic forces, were quantitatively examined and verified. This work offers good data to understand noise and vibration characteristics of circulator pumps and the relationships among the noise, vibration and unsteady flow structures. 相似文献
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由曲柄连杆机构驱动的普通活塞式空压机存在噪声、振动和缸体磨损等问题,提出双曲柄连杆机构驱动的活塞式空压机来解决这些问题;同时设计了基于对称双曲柄活塞驱动的二次增压双作用空压机和双级双作用空压机,提高了空压机的输出压力和流量,并可实现低压大流量和高压小流量的输出控制;降低空压机的振动和噪声,提高平稳性,降低活塞和气缸缸体的磨损,提高空压机的使用寿命。 相似文献
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往复压缩机噪声诊断及降噪研究 总被引:3,自引:0,他引:3
对全封闭往复压缩机进行了声功率、声压级、壳体振动和壳体模态试验,分析了压缩机主要振动和噪声源.确定了壳体的振动模态,指出了进一步降低压缩机噪声的途径。确定2500Hz和3150Hz的峰值噪声主要是壳体的辐射噪声,并且采取了两种降噪措施,经试验比较,降噪效果明显。 相似文献
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Experimental investigation on the flow-induced noise under variable conditions for centrifugal pumps 总被引:1,自引:0,他引:1
With extensively using of centrifugal pumps,noise generation in these pumps is increasingly receiving research attention in recent years.The noise sources in centrifugal pumps are mainly composed of mechanical noise and flow-induced noise.And the study of flow-induced noise has become a hotspot and important domain in the field.The flow-induced noise closely related to the inner pressure pulses and vibration of volute in pumps,therefore,it is necessary to research the interaction and mechanism among them.To investigate the relationships,a test system is designed which includes a test loop and a measurement system.The hydrophones and pressure sensors are installed on the outlet of the pump and vibration acceleration sensors are disposed on the pump body.Via these instruments,the signals of noise,pressure pulses and vibration are collected and analyzed.The results show that the level of flow-induced noise becomes smaller as the flow increment during low flow rate operations,and it is steadily close to the design point,then it increases with the growing of flow rate in high flow rate conditions.Furthermore,there are some similar peak points in the power spectrum charts of noise,pressure pulses and vibration.The broadband noise at low flow rate is mostly focused on the region of 0-40 times shaft frequency,which is mostly made by rotating stall and vortex;while the noise at high flow rate conditions is focused on the region of 60-100 times shaft frequency,which may be mostly made by cavitations.The proposed research is of practical and academic significance to the study of noise reduction for centrifugal pumps. 相似文献
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研究了基于独立分量分析(independent component analysis,简称ICA)的发动机振动信号盲源分离技术,旨在将发动机振动信号按照不同的激振源进行分离。首先阐述了基于最大信噪比的盲源分离算法原理,通过对仿真信号进行分离,判断了分离输出信号与仿真信号的一致性,验证了该算法的可行性;然后将该算法与FFT分离法相结合,应用于某型双转子航空发动机高、低压转子实测振动信号盲源分离中,取得了很好的分离效果,表明应用ICA技术建立的基于最大信噪比的盲源分离算法具有迭代次数少、计算复杂度低、效果好及稳定等优点。 相似文献
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