水压柱塞泵配流盘阻尼槽结构优化及试验研究

针对水压柱塞泵U形阻尼槽的结构参数进行研究,通过流场仿真对比不同阻尼槽结构参数下水压柱塞泵的流量特性,确定水压柱塞泵的压力、流量脉动率最优的阻尼槽结构参数,从而降低水压柱塞泵的流体振动。仿真结果表明,在现有结构参数下当水压柱塞泵阻尼槽宽度设置为2mm、深度为0.8mm、配流盘预升/泄闭死压角为11.8°时,柱塞泵的压力和流量脉动率最小。开展了水压柱塞泵的振动试验,对比了阻尼槽优化前后的试验数据,试验结果表明优化后的阻尼槽结构能够有效降低水压柱塞泵的振动。     

液压柱塞泵压力脉动函数的仿真分析

流量脉动会引起压力脉动,从而影响液压系统的工作性能,引起结构振动和辐射噪声,会造成液压元件和系统的疲劳破坏,因此仿真分析流量脉动和压力脉动函数对于有效抑制液压柱塞泵的振动和正确设计液压柱塞泵具有重要价值。笔者针对液压泵系统进行定量的振动与噪声分析时所必须具备的激励函数,首先,详细分析了液压泵系统的运行特性,采用傅里叶(Fourier)级数模拟液压泵系统激励函数;然后,建立了压力脉动函数模型;最后,模拟了压力脉动的函数曲线,解决了液压泵系统振动与噪声分析所必需的激励问题。该文为进一步研究液压柱塞泵的定量振动与噪声的响应提供了脉动激励描述,具有理论意义和实际应用价值。     

非对称轴向柱塞泵配流副压力脉动特性分析

为了节省功率电传系统的安装空间和重量,需要用泵直接闭环控制差动缸运动,将泵的吸油配流窗口改为2个窗口,以匹配差动缸的面积比。该结构变化导致其压力脉动增大,产生大的振动噪声,为了减小其影响,提出了一种阻尼槽-缓冲容腔-导油槽非对称配流盘结构,针对该结构开展了非对称配流流量特性的内部流场仿真分析,并通过了压力脉动特性试验验证。结果表明了非对称轴向柱塞泵的配流结构设计与仿真的合理性,实现了液压泵的新功能。     

基于虚拟样机的轴向柱塞泵动态特性仿真研究

为研究轴向柱塞泵的动态特性,理论分析了其运动特性和流量脉动特性,并基于ADAMS与AMESim软件建立了某型柱塞泵的虚拟样机模型。通过联合仿真得到了不同转速下的柱塞位移、速度、加速度曲线,不同转速、斜盘倾角下的流量脉动曲线,以及不同负载下的传动轴转矩、泵出口压力曲线。研究结果表明:为减小柱塞泵的振动与噪声,其转速应限制在一定范围内;适当提高转速、减小斜盘倾角可减小流量脉动。研究结果可为柱塞泵结构优化提供参考依据。     

基于PumpLinx纯水轴向柱塞泵配流盘卸荷槽结构的仿真分析

以纯水轴向柱塞泵为研究对象,在同时考虑配流盘间隙和柱塞间隙的基础上,利用流体仿真分析软件PumpLinx,采用动网格技术并建立空化模型,研究配流盘减振结构对流量特性和压力脉动的影响。通过仿真分析U型槽、三角槽、孔槽结合和无阻尼槽四种不同的减振方案在配流过程中的压力脉动和流量脉动,进而比较得出最佳的高压卸荷槽结构。仿真结果表明,采用U型槽结构的配流盘在预升压过程中优于其他三种结构,且其出口的流量更加平稳,脉动率更小。     

变排量非对称轴向柱塞泵控制性能分析

变排量非对称轴向柱塞泵直接控制非对称液压缸闭式系统具有能效高、结构紧凑等优势。针对变排量三配流窗口轴向柱塞泵存在变量阻力矩脉动大、斜盘倾角振荡频率高等问题,提出在变排量机构中增加阻尼孔以提高变排量控制性能的方案,推导了变排量控制系统的传递函数;通过AMESim仿真模型分别研究了有无阻尼孔情况下的斜盘倾角振荡、变量缸活塞受力、斜盘变量阻力矩等。结果表明,在控制系统阀控缸中加入直径2 mm的阻尼孔,能有效降低斜盘倾角的振荡频率,减小系统脉动冲击。     

负载敏感系统压力脉动控制方法的研究

针对掘进机星轮马达空载转动时变量泵出口压力脉动剧烈的问题,采用理论分析、AMESim仿真和实验验证相结合的方法开展研究,结果表明摩擦力矩周期性变化是造成变量泵压力脉动的主要影响因素,并提出了在变量泵LS反馈油路设置阻尼的方法,降低负载敏感系统压力脉动。数字仿真和试验结果表明,LS反馈油路设置阻尼能有效地降低变量泵出口的压力脉动。     

基于小波包变换的柱塞泵脉动压力信号BP故障诊断

为了提高柱塞泵脉动压力信号的故障诊断诊断能力，分别提取得到正常的泵脉动压力与齿圈出现磨损故障时对应的泵脉动压力，利用小波包变换的方法消除原始信号的噪声信号，再提取得到由故障信息构成的频段，完成信号时域特征的分析。频段介于0～4 kHz之间时，在柱塞泵脉动压力信号中形成了泵轴频、基频与谐倍频等，含有泵运行过程的各项信息参数，处于高频区间时，发生了线谱幅值的持续减小。利用MATLAB软件建立BP网络故障诊断结果表明：脉动压力指标可以实现柱塞泵内部运行情况的准确识别，达到故障诊断的测试要求。方法在诊断方面是有效的，在处理柱塞泵脉动压力信号故障诊断领域具有很好的实际指导意义。     

利用倒频谱诊断液压泵早期故障

这里通过对轴向柱塞泵振动信号的监测，利用振动信号的功率谱和倒频谱分析法，诊断轴向柱塞泵的松靴故障，结果显示振动信号的倒频谱可以及时发现早期松靴故障，而其功率谱则不太敏感。     

基于虚拟样机的轴向柱塞泵压力脉动特性研究

介绍了虚拟样机技术在轴向柱塞泵仿真研究中的应用。借助虚拟样机技术并根据柱塞泵的物理模型参数,分别在MSC.ADAMS和AMESim环境下构建了柱塞泵的动力学模型和液压模型。利用二者模型的底层接口,搭建了液固耦合的轴向柱塞泵虚拟样机模型。基于虚拟样机,研究了油液黏度、体积弹性模量对柱塞泵出口压力脉动特性的影响,得到了泵出口压力脉动幅值及脉动率随体积弹性模量增大而增大的线性关系,也总结出了泵出口压力脉动幅值及脉功率随油液黏度增大而增大但变化幅度逐渐减小的结论。     

配流盘对轴向柱塞泵声振特性的影响

通过振动和噪声测试试验台,在两种不同的试验工况下,分别对轴向柱塞泵的表面振动速度和声压级进行了测试。使用傅里叶变换对测试数据进行处理,分析了不同试验工况下轴向柱塞泵的声振特性,探讨了振动速度和声压级之间的对应关系。然后对比了两种配流盘结构对声振特性的影响,给出了阻尼孔以及三角槽结构的配流盘的适用范围和各自的优势,为不同工况下轴向柱塞泵配流盘结构的选择提供了一定的参考。     

Noise Reduction of an Axial Piston Pump by Valve Plate Optimization

Current researches mainly focus on the investigations of the valve plate utilizing pressure relief grooves. However,air?release and cavitation can occur near the grooves. The valve plate utilizing damping holes show excellent perfor?mance in avoiding air?release and cavitation. This study aims to reduce the noise emitted from an axial piston pump using a novel valve plate utilizing damping holes. A dynamic pump model is developed,in which the fluid properties are carefully modeled to capture the phenomena of air release and cavitation. The causes of di erent noise sources are investigated using the model. A comprehensive parametric analysis is conducted to enhance the understanding of the e ects of the valve plate parameters on the noise sources. A multi?objective genetic algorithm optimization method is proposed to optimize the parameters of valve plate. The amplitudes of the swash plate moment and flow rates in the inlet and outlet ports are defined as the objective functions. The pressure overshoot and undershoot in the piston chamber are limited by properly constraining the highest and lowest pressure values. A comparison of the various noise sources between the original and optimized designs over a wide range of pressure levels shows that the noise sources are reduced at high pressures. The results of the sound pressure level measurements show that the optimized valve plate reduces the noise level by 1.6 d B(A) at the rated working condition. The proposed method is e ective in reducing the noise of axial piston pumps and contributes to the development of quieter axial piston machines.     

变分模态分解与极限梯度提升树融合的高速轴向柱塞泵空化等级识别

针对高速轴向柱塞泵在不同空化程度下故障特征不明显导致识别准确率低的问题,提出了一种变分模态分解和极限梯度提升树融合的识别方法。在不同空化等级下进行高速轴向柱塞泵空化试验,采集壳体的振动加速度信号,对信号采用变分模态分解方法并从中提取故障特征以构造特征数据集,最后利用极限梯度提升树进行空化等级的识别。为证明所提方法的抗噪性能,在测试集中加入了随机高斯白噪声。结果表明,加入不同信噪比的噪声后,该识别模型仍能准确地识别出高速轴向柱塞泵的空化等级。     

Fault diagnosis of axial piston pumps with multi-sensor data and convolutional neural network

Axial piston pumps have wide applications in hydraulic systems for power transmission. Their condition monitoring and fault diagnosis are essential in ensuring the safety and reliability of the entire hydraulic system. Vibration and discharge pressure signals are two common signals used for the fault diagnosis of axial piston pumps because of their sensitivity to pump health conditions. However, most of the previous fault diagnosis methods only used vibration or pressure signal, and literatures related to multi-sensor data fusion for the pump fault diagnosis are limited. This paper presents an end-to-end multi-sensor data fusion method for the fault diagnosis of axial piston pumps. The vibration and pressure signals under different pump health conditions are fused into RGB images and then recognized by a convolutional neural network. Experiments were performed on an axial piston pump to confirm the effectiveness of the proposed method. Results show that the proposed multi-sensor data fusion method greatly improves the fault diagnosis of axial piston pumps in terms of accuracy and robustness and has better diagnostic performance than other existing diagnosis methods.     

Experimental investigation on the flow-induced noise under variable conditions for centrifugal pumps

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.     

基于有限元的斜盘式柱塞泵减震技术研究

液压泵是液压传动系统的动力元件,其中柱塞泵零件多,转速高,随着主轴转速的提高,柱塞泵振动和噪声也迅速加大。针对以上存在的问题,利用有限元技术,对优化后的壳体模型进行了计算模态分析,分析结果表明优化后壳体的固有频率值与激振源的频率值能够在一定程度上错开从而避免共振现象,找到了降低泵壳表面声辐射的途径,从而找到一种降低柱塞泵噪音的方法,降低了结构振动和噪声。     

多级离心泵创建压力室平衡轴向力的试验研究

可靠的轴向力平衡装置是高压多级离心泵实现长期安全运行的重要机构。针对高压离心泵对运行可靠性和使用寿命的要求,创新设计了一种压力室平衡装置自动平衡高压离心泵的轴向力。在流力基本理论指导下基于试验流体力学方法研究了3个阻尼孔直径对整机效率、流量、压力、功率的影响。针对D25-30×5多级离心泵,通过试验确定了在阻尼孔直径为ф4~6mm时,得到了较高的整机效率η=0.701~0.802,效率比原平衡盘结构最大提高18%。机组运行振动小、噪声低,能长时间平稳可靠工作。     

奇异值小波降噪法在柱塞泵振动信号处理中的应用

针对小波阈值和奇异值分解降噪法的不足,研究一种新的小波阈值函数。提出一种基于改进阈值的奇异值小波降噪方法,该方法利用奇异值分解技术,将噪声非均匀分布的信号正交分解为噪声分布相对均匀的分量,并对每个分量进行小波阈值降噪,重构降噪后的分量,得到降噪信号。仿真实例证明,该方法与小波软、硬阈值及改进阈值法相比,不仅提高信噪比,而且能够更好地消除高斯噪声。利用该方法对柱塞泵不同状态振动信号进行降噪,结果表明,该方法能有效抑制噪声,为柱塞泵振动信号预处理提供一种更为有效的方法。     

轴向柱塞泵降噪分析与研究

轴向柱塞泵在某平地机装机试用过程中出现啸叫的现象,通过原型泵和故障泵噪声对比测试分析,判断柱塞泵噪声异常是由于配流盘过渡区采用小孔阻尼引起的。根据对配流盘的计算分析、CFD仿真,认为配流盘过渡区小孔阻尼结构会导致柱塞腔较大的压力冲击,从而产生较大的流体噪声。将配流盘过渡区小孔结构改进为三角槽结构后,降噪效果得到显著的改善。