磁力弹簧式压电共振型气泵的设计

利用压电振子的振动激励相连接的隔膜共振原理,提出了用磁力弹簧式压电共振型气泵来提高压电泵对气体的驱动能力.首先,分析磁力弹簧式共振泵的工作原理,建立了共振泵的动力学模型,计算得出了影响隔膜振幅的主要因素.接着,设计和制作了样机,使用阻抗分析仪和激光位移计分别测得系统的共振频率及压电振子的位移放大倍数.最后,设计了测量共振泵流量和输出压力的实验装置,得出了磁力弹簧轴向间距对输出流量和输出压力的影响.实验测试表明:当输入正弦电压为200 V,系统共振频率为134 Hz,磁力弹簧的轴向间距为9 mm时,压电振子的位移放大倍数约为4.3,其最佳输出流量为524 ml/min,最佳输出压力为9.2 kPa.结果显示,提出的磁力弹簧式压电共振型气泵提高了气体的输送能力.     

四腔并联压电泵结构设计

为提高压电泵的输出性能,设计了一种层叠型四腔并联有阀压电泵。在80 V正弦交流电驱动下,40~400 Hz工作频率内,以水和空气作为介质,分别选用不同数量的压电振子进行驱动,在不同的驱动方式(指振子间工作时的相位差)下对泵的输出性能进行试验测试。结果显示,当泵送空气时,不管多少个振子进行驱动,驱动方式对泵的输出流量几乎不产生任何影响,在测试频率范围内,输出流量随频率成线性变化,最大输出气体流量可达3600 mL/min;当泵送液体时,驱动方式对泵的输出流量影响很大,当同侧的压电振子为异步驱动时,输出流量的效果更好,在工作频率180 Hz时,最大输出液体流量可达830 mL/min。试验结果为多振子驱动压电泵选择合适的振子间驱动方式提供了参考依据。     

压电双晶片和单晶片驱动下泵的输出性能研究

为从理论上获得压电泵在薄片型压电双晶片和单晶片(统称压电振子)驱动时的输出流量关系,需要获得二者振动时产生的容积变化量。假设压电振子在周边固定约束条件下,应用弹性薄板的小挠度弯曲变形理论,推导了压电双晶片和单晶片振动时的容积变化方程,并根据方程对铜基板直径为35mm,压电陶瓷直径为29mm,基板和压电陶瓷厚度同时为0.2mm和0.3mm 2种规格的压电单晶片和双晶片进行了振动容积计算。计算结果显示,相同基板和陶瓷厚度的双晶片振动产生的容积变化量是单晶片的2.3倍。将上诉压电振子应用到单腔压电泵上进行输送气体流量测试,获得的实际输出流量比在1.5~2倍之间,理论计算结果与试验测试结果比较接近。理论推导结果为比较双晶片和单晶片驱动下压电泵的输出能力提供了可靠依据。     

单振子双腔体无阀压电泵结构设计与机理分析

提出了一种单振子双腔体无阀压电泵,应用小挠度弹性弯曲理论导出了圆形复合压电振子的弹性曲面微分方程,分析了采用一个压电振子形成两个工作腔体压电泵的结构和工作机理,并与单振子单腔体压电泵对比分析了该结构与输出流量的关系。设计研制了结构独特、输出性能更高的单振子双腔体无阀压电泵,通过试验表明:单振子双腔体无阀压电泵比单振子单腔体无阀压电泵输出流量有明显提高。     

非对称分叉流管无阀压电泵的设计及试验

具有微混合功能的多级Y型流管无阀压电泵存在着输出流量与振子带载能力不平衡的问题。为此，提出了一种非对称分叉流管无阀压电泵。首先，理论分析了该无阀压电泵输出流量与流管流阻间的关系；其次，利用有限元软件数值计算了多级Y型流管的流阻特性；最后，采用光固化快速成型技术加工了样机，并进行了泵特性试验和振子振动测试。试验结果表明：在峰峰值200 V正弦波交流电驱动下，该压电泵的流量、扬程和压电振子的振幅都随驱动频率增加呈现先增大后减小的趋势；当驱动频率为31 Hz时，最大流量为4 g/min；驱动频率为38 Hz时，最大扬程为40.5 mmH2O。在试验施加电压范围内，该泵的输出性能与驱动电压呈正相关性。本研究验证了非对称流道树型无阀压电泵的可行性，为非对称无阀压电泵在微流道滴灌和微混合等领域的应用提供了参考。     

Principle and experimental verification of caudal-fin-type piezoelectric-stack pump with variable-cross-section oscillating vibrator

In the traditional flow-resistance-differential (FRD) type valve-less piezoelectric pump,the generated outflow and pressure are discontinuous because of the inherent periodicity and fluctuation of the pump.To overcome these drawbacks,utilizing the bending vibration of piezoelectric bimorph to drive fluid was conducted.However,our investigation on the current status of this piezoelectric bimorph pump shows that larger driving force and vibration amplitude are required for fluid pumping;the pumping can be realized through the centrifugal force;and the mechanism of fluid pumping is no longer further studied.Based on these cases,the paper designed a piezoelectric-stack pump with variable-cross-section oscillating (VCSO) vibrator by imitating the swing of the caudal-fin of tuna,and the pump is neither the rotating type nor the volumetric type according to the taxonomy.The interaction between the oscillating vibrator and the fluid parcel is firstly analyzed from the viewpoint of momentum conservation,and the analytical expression of pump flow rate is obtained.Then the modal and harmonic response analyses on the vibrator immerged in water are carried out.From the analyses the first two orders resonance frequencies are 832 Hz and 1 939 Hz,respectively,and the peak value of the tip amplitude is 0.6 mm.Laser Doppler vibrometer is used to measure both the frequency and vibration amplitude,and the determined first two orders resonance frequencies are 617 Hz and 1 356 Hz,respectively.The measured tip amplitude reaches to the peak value of 0.3 mm.At last,experimental measurement for the flow rates with different driving frequencies is conducted.The results show that the flow rate can reach 560 mL/min at 1 370 Hz when the pump runs under the backpressure of 30 mm water column.And the flow rate is as much as 560% of that of experiment results carried out by researchers from Brazil.The proposed pump innovates in both theory and taxonomy;in addition,the pump overcomes the drawbacks such as large flow fluctuation and low flow rate     

Novel piezoelectric pump with “E”-shaped valve found from sub-experiments

Increasing the driving frequency of a piezoelectric vibrator can resolve the bottleneck of low flow in a valve piezoelectric pump. However, a piezoelectric pump of a traditional valve body presents the hysteretic nature of the valve, and macroscopic performance is up-frequency to flow-sharply. This research is to settle the bottleneck mentioned above. First, through the sub-experiment on various parameters of the plate valve of a piezoelectric pump, the reasons why a valve body itself can influence “up-frequency to flow-sharply”, which causes the hysteretic nature of the valve, were discovered. Second, an “E”-shaped valve and piezoelectric pump with an “E”-shaped valve (PPEV) were invented. Finally, the efficiency of PPEV has been proved helpful to reduce hysteretic nature in experiments. Under the similar conditions, compared with traditional pumps, the driving frequency of novel PPEV can be more than 10 times high, and the flow rate also can be several times high.     

Novel piezoelectric pump with “E”-shaped valve found from sub-experiments

Increasing the driving frequency of a piezoelectric vibrator can resolve the bottleneck of low flow in a valve piezoelectric pump. However, a piezoelectric pump of a traditional valve body presents the hysteretic nature of the valve, and macroscopic performance is up-frequency to flow-sharply. This research is to settle the bottleneck mentioned above. First, through the sub-experiment on various parameters of the plate valve of a piezoelectric pump, the reasons why a valve body itself can influence “up-frequency to flow-sharply”, which causes the hysteretic nature of the valve, were discovered. Second, an “E”-shaped valve and piezoelectric pump with an “E”-shaped valve (PPEV) were invented. Finally, the efficiency of PPEV has been proved helpful to reduce hysteretic nature in experiments. Under the similar conditions, compared with traditional pumps, the driving frequency of novel PPEV can be more than 10 times high, and the flow rate also can be several times high.     

双作用压电泵绝缘压电振子的研究

为了提高压电泵的工作效率,提出了对压电泵中的动力元件-压电振子进行特殊绝缘处理,使压电振子在两个方向弯曲变形时都可以形成输出工作能力,即双面作用的绝缘压电振子。阐述了由一个绝缘压电振子形成两个工作腔体的双作用压电泵结构。根据小挠度弹性弯曲理论导出了绝缘圆形复合压电振子的弹性曲面微分方程,阐述了绝缘处理方案和过程,并对其绝缘特性进行分析。对绝缘压电振子进行了实验测试,实验结果表明：双作用绝缘压电振子不仅具有绝缘特性,而且具有良好的韧性和强度;其击穿电压比未绝缘处理压电振子的击穿电压提高了20～30V。为相关产品开发和科研提供了一种新型双面作用的压电驱动元件。     

组合式压电驱动芯片水冷系统

为了提高压电驱动芯片水冷系统的适用性、可维护性以及冷却效率,本文提出一种组合式压电驱动芯片水冷系统。首先,测试和分析了芯片水冷系统中组合式泵单元在220Vpp方波驱动下不同组合方式(串/并联)、泵工作数量以及相对位置时的输出性能,接着,基于组合式泵单元的试验结果进行芯片水冷系统的水冷效果研究。实验结果表明:串联组合双泵工作时,双泵位于串联组合首尾位置(AD)时性能较优,在30Hz时获得最大输出压力(25kPa);串联组合四泵工作时,分别在35Hz和55Hz获得了最大压力(23.5kPa)和最大流量(13.5mL/min);并联组合双泵工作时,双泵都位于组合首位(AC)时性能较差;并联组合四泵工作时,分别在50Hz和60Hz获得最大输出流量(22mL/min)和最大输出压力(12.6kPa);通过串并联以及泵工作数量的切换获得了芯片水冷系统的冷却效果,不同的组合方式以及泵工作数量可以获得不同的冷却效果。获得了组合式压电驱动芯片水冷系统的驱动参数,为计算机芯片有效散热提供一条新途径。     

压电叠堆泵微位移放大机构的试验研究

提出了一种应用于压电叠堆泵的微位移放大机构,该机构以压电叠堆(积层式压电微位移器)为驱动元件,通过基于三角形放大原理的柔性铰链放大机构,放大压电叠堆的输出位移.同时,设计、研制了实验装置,并在试制样机上对其静、动态特性进行了实验.实验测试结果表明,该机构具有线性良好、高分辨率和高频响应等特点.     

菱形压电微位移放大机构的设计

为提高叠层压电陶瓷作动行程,并使之具有往复对称作动的特性,提出一种基于三角放大原理的菱形压电微位移放大机构。该机构以叠层压电陶瓷作为驱动元件,利用三角位移放大原理,在放大叠层压电陶瓷位移输出的同时,实现在平衡位置两侧的双向主动输出。提出了相应的驱动方法,实现了对该机构输出方向和大小的控制。分析了机构的工作原理,通过解析计算得到该机构的理论放大倍数为2.9,与所建立有限元模型通过仿真计算得到放大倍数2.5相近。制作了试验样机并进行了试验验证,结果显示:该机构在驱动电压为200V时最大输出位移为(32±16)μm,对叠层压电陶瓷位移输出的放大比例为2.4倍,与理论计算相近;频率响应试验表明信号频率对位移输出影响较小。提出的设计方案实现了位移放大和位移双向主动输出这两个预期目标。     

环形压电双晶片驱动式振动送料器

为了满足现代工业领域中对轻、薄、小产品平稳输送的要求,提出了一种采用环形压电双晶片作为驱动源的新型振动送料器。设计了振动送料器结构,分析了振动送料器的工作原理,测试了压电双晶片振子的性能,利用有限元软件ANSYS确定了压电双晶片振子的工作模态,研制了送料器样机并进行试验测试。试验结果表明：当振动频率为86.5～91.5Hz时,送料器具备输送物料的能力;当系统共振时,输送速度最快,随着电压的增加,送料速度呈线性关系增加;与同型号的电磁振动送料器相比,研制的环形压电双晶片驱动式振动送料器消耗电流仅为其16%,工作噪声下降22dB,输送稳定性好。     

一种仿生型无阀压电泵

针对传统的容积型流阻差式无阀压电泵具有吸入周期和排出周期,存在着流动脉动大、流量小的问题,提出一种新型的鱼鳍摆动式无阀压电泵。模仿在鱼类中巡游速度最快的金枪鱼的鱼体结构,设计了压电双晶片结构的压电振子,并将其尾鳍设计成柔性叶片状。分析了压电双晶片结构悬臂梁的受力变形、模态振型在机电转换效率方面的关系。研制了泵的样机并测量了激励电压在100 V时泵的流量。实验结果表明:振子工作在1阶振型时,泵水效应不明显;振子工作在2阶振型时,谐振频率为740 Hz,泵的流量为266 mL/min;振子工作在3阶振型时,谐振频率为1 280 Hz,泵的流量为105 mL/min。     

液压微位移放大器响应频率的研究

研究了一种基于液压原理的微位移放大器,微小位移可通过液压放大可转化为具有实际应用价值的输出位移。对微位移放大器的动态特性进行了建模分析,将放大机构与压电叠堆执行器相耦合,得到了该微位移放大器系统的传递函数。讨论了两个弹簧刚度k₁和k₂对响应频率和放大倍数的影响,为实际设计研究提供理论支持。     

钹型开槽式阀压电泵的设计

由于有阀压电泵内部阀体所受应力过大易导致阀体失效,本文提出了钹型开槽式截止阀来减小有阀压电泵内部阀体所受应力。基于钹型开槽式截止阀设计了有阀压电泵,分析了钹型开槽式阀压电泵的工作原理。对钹型开槽膜片进行了受力分析,研究了该压电泵的输出性能及耦合作用下的膜片应力。加工制作了钹型开槽式阀压电泵样机,建立了钹型开槽式阀压电泵的有限元模型,数值计算了流固耦合作用下的阀体应力值。计算结果表明:在压电泵正常输出的驱动频率范围内,当驱动频率为418Hz时,膜片所受应力的计算值也达到最大,为81.74 MPa。最后,进行了压电泵性能试验。试验结果显示:该压电泵的输出流量最大值和振子振幅最大值均出现在低频段;当驱动电压为160V,驱动频率为5Hz时,输出流量达到最大,为6.6g/min;驱动频率为4Hz时,压电振子振幅达到最大,为165.8μm。文中的研究验证了钹型开槽式阀体压电泵的有效性,并得出当钹型开槽式阀压电泵工作在低频段时,阀门所受应力远小于高频段时阀门的应力值。     

Effects of Driving Mode on the Performance of Multiple-Chamber Piezoelectric Pumps with Multiple Actuators

Due to the limited output capability of piezoelectric diaphragm pumps, the driving voltage is frequently increased to obtain the desired output. However, the excessive voltage application may lead to a large deformation in the piezoelectric ceramics, which could cause it to breakdown or become damaged. Therefore, increasing the number of chambers to obtain the desired output is proposed. Using a check-valve quintuple-chamber pump with quintuple piezoelectric actuators, the characteristics of the pump under different driving modes are investigated through experiments. By changing the number and connection mode of working actuators, pump performances in terms of flow rate and backpressure are tested at a voltage of 150 V with a frequency range of 60 Hz ?400 Hz. Experiment results indicate that the properties of the multiple-chamber pump change significantly with distinct working chambers even though the number of pumping chambers is the same. Pump performance declines as the distance between the working actuators increases. Moreover, pump performance declines dramatically when the working piezoelectric actuator closest to the outlet is involved. The maximum backpressures of the pump with triple, quadruple, and quintuple actuators are increased by 39%, 83%, and 128%, respectively, compared with the pump with double working actuators; the corresponding maximum flow rates of the pumps are simply increased by 25.9%, 49.2%, and 67.8%, respectively. The proposed research offers practical guidance for the effective utilization of the multiple-chamber pumps under different driving modes.     

块体物料的超声振动输送及同步驱动

针对小块体物料的短距离精密输送问题,提出超声振动输送新方法,设计制作了基于弯曲行波的环形压电输送振子。依据模块化设计思想,将输送装置设计成3个单一输送振子的并列组合,采取多个振子的同步驱动。对所设计振子的模态及同步驱动特性进行了理论分析与实际测试,试验结果验证了超声振动输送装置同步驱动的可行性。     

层叠型双腔并联压电泵性能研究

为提高层叠型双腔并联压电泵的输出性能,在出口通孔处设计了隔板结构,以阻止流体同时出流时产生的正向碰撞和向对面腔内回流问题。采用液体水和空气作为输送介质,对试验样机进行了试验测试,结果表明:隔板结构可以大幅度提高层叠型双腔并联压电泵输送液体介质的能力,在80 V正弦交流电驱动下,最大输出流量可达460 mL·min^-1,与没有隔板结构比较,输出流量可提高约30%。对该结构压电泵单个振子驱动与2个振子驱动时的关系进行了试验验证,结果表明:当工作介质为气体时,不管是同步驱动或异步驱动,2个振子工作时输出流量约为2个单个振子独立工作时输出流量之和;当工作介质为液体时,在2个振子同步驱动时输出流量出现小于单个振子工作时的输出流量情况,而异步驱动输出流量约为2个单个振子独立工作时输出流量和的1.4倍。     

仿鱼摆动式无阀压电泵的新进展

近年来,随着医疗、卫生和保健领域的发展,对压电泵、特别是无阀压电泵的微型化、传输流体的稳定性、流动脉动及回流等方面提出了更高的要求。容积型压电泵因其固有的周期性、波动性而不能产生连续输出和压力,同时回流、脉动现象或微型阀片阻塞现象无法避免;回转型压电泵因其固有的复杂性和难控性无法满足体内输送的安全及稳定的需要。因此,探索新型工作原理的压电泵尤为重要。基于摆动驱动形成流体单向流动的现象,综述了南京航空航天大学机械结构力学及控制国家重点实验室流体驱动研究小组近年来对3种非容积型、非回转型的仿鱼尾摆动式无阀压电泵研究成果。