磁力弹簧式共振型压电气泵研究

发布时间：2018-07-20 22:01

【摘要】：气体隔膜泵是一种小型的流体泵，近年在医药生物、精细化工、航空航天、微机电系统等领域得到了广泛的应用。目前市场上的气体隔膜泵主要有利用电机凸轮机构驱动的电磁隔膜泵和利用压电振子驱动的压电隔膜泵两大类，电磁隔膜泵在实际应用过程中会存在结构复杂、成本高、噪声大等问题；而压电隔膜泵则存在容积变化率低、压电振子过热、易碎裂、易退极化等问题。本文结合国家自然科学基金项目《压电型气体隔膜泵设计理论与关键技术研究》（项目编号：50735002）的研究，首次提出将磁力弹簧用于构造共振泵，研究了相关理论与技术问题。将磁力弹簧用于共振气泵研究的优点是它可以增加泵体的容积变化率，还可以使系统结构简化、降低噪音并且增加系统的可靠性和稳定性，最重要的是可通过调整磁力弹簧的轴向间隙来改变机械系统的刚度，进而十分方便的调整整个机械系统的共振频率。压电振子是磁力弹簧共振泵的核心部件，为整个共振系统提供激励。本文采用的压电振子是环形压电陶瓷与环形基板利用环氧树脂粘接而成，将压电振子作为磁力弹簧共振泵激振体的一部分，对其进行仿真，，通过激振体的模态分析和谐响应分析，确定了压电振子的最终结构参数。利用磁荷观点对磁力弹簧的轴向力进行理论推导，并且通过划分单元格，采用离散求和的方法和并结合matlab编程计算了磁力弹簧的轴向力和轴向间距的关系，然后利用曲线拟合的方法求出其关系式，得出磁力弹簧的轴向刚度和轴向间距的关系。并且通过设计试验对所用磁力弹簧的轴向力进行了测量，同样利用对拟合曲线求导的方法得出轴向刚度和轴向力的关系。对磁力弹簧式共振气泵的工作原理进行了介绍，对共振体的工作原理进行定性的分析，分析了磁力弹簧对整个激振体的作用；并设计了主要部件，建立了激振体部分的动力学模型，得到影响激振体位移的因素；对主要部件的刚度进行了计算；利用精密阻抗分析仪和激光测微仪分别对激振体的共振频率和激振体的位移进行测量，得到激振体的共振频率与磁力弹簧轴向间距的关系，并与压电振子中心点的位移量进行了比较，得出共振泵激振体的位移放大倍数。对磁力弹簧式共振泵泵体的基本结构和工作过程进行详细的介绍，利用板壳理论对泵体隔膜进行了优化，最终确定了隔膜的结构参数;详细分析腔体的容积变化率、流体流态以及阀的滞后性对泵性能的影响;设计性能测试装置，并以测试结果为依据又选则了阀的阀堵直径、悬臂宽度，腔体高度以及阀座的预紧高度，最终确定共振泵泵体最佳结构参数。分析了导致压电振子在竖直方向扭转的原因，由于加工误差的存在，实际上共振泵中磁力弹簧的轴向刚度与理论计算值不太一致，磁力弹簧的两磁铁在轴向上并不是完全同心的，这样就会在原来只有一个轴向力的基础上额外的产生一个径向力，径向力和轴向力会对与悬浮磁铁相连接的压电振子产生力矩，随着轴向间隙的减小，径向力越来越大，两环形磁铁偏心越来越严重。因此磁力弹簧的实际轴向刚度要比理论计算值要小，而径向刚度则会增加。磁力弹簧共振泵成功的关键在于磁力弹簧轴向刚度的控制、增加压电振子的激励以及提高压电振子激励的利用效率。磁力弹簧轴向刚度的控制可以借鉴磁悬浮列车以及磁力轴承所取得的研究成果；增加压电振子的激励的关键在于寻求具有优质性能参数的压电陶瓷来制作压电振子；而提高压电振子激励的利用效率则必须通过完善共振泵结构设计来实现。
[Abstract]:Gas diaphragm pump is a small type of fluid pump. It has been widely used in medicine, biology, fine chemical industry, aerospace, MEMS and other fields in recent years.
At present, there are two main types of gas diaphragm pumps in the market, such as electromagnetic diaphragm pump driven by motor cam mechanism and piezoelectric diaphragm pump driven by piezoelectric vibrators. In practical application, the electromagnetic diaphragm pump will have problems such as complex structure, high cost and large noise, while the piezoelectric diaphragm pump has low volume change rate and a piezoelectric vibrator. Heat, fragility, depolarization, and other problems.
In this paper, based on the study of the design theory and key technology of the piezoelectric gas diaphragm pump, the National Natural Science Foundation of China (project number: 50735002), the magnetic spring is first applied to the structural resonance pump, and the related theoretical and technical problems are studied.
The advantage of applying the magnetic spring to the study of the resonant gas pump is that it can increase the volume change rate of the pump body, simplify the structure of the system, reduce the noise and increase the reliability and stability of the system. The most important thing is that the stiffness of the mechanical system can be changed by adjusting the axial gap of the magnetic spring, and then it is very convenient to adjust the whole system. The resonance frequency of a mechanical system.
The piezoelectric vibrator is the core component of the magnetic spring resonance pump, which provides the excitation for the whole resonance system. The piezoelectric vibrator used in this paper is a ring piezoelectric ceramic and a ring substrate which is bonded with epoxy resin. The piezoelectric vibrator is used as part of the resonant pump of the magnetic spring pump, and it is simulated by the modal analysis of the vibrator. The final structural parameters of the piezoelectric vibrator are determined by response analysis.
The axial force of the magnetic spring is theoretically derived from the magnetic charge viewpoint, and the relation between the axial force and the axial distance of the magnetic spring is calculated by the method of discrete summation and MATLAB programming by dividing the cell. Then the relation formula is obtained by the curve fitting method, and the axial stiffness and the axial interval of the magnetic spring are obtained. The axial force of the magnetic spring is measured by the design test, and the relationship between the axial stiffness and the axial force is also obtained by using the method of fitting the fitting curve.
The working principle of the magnetic spring type resonant gas pump is introduced, the working principle of the resonance body is analyzed qualitatively and the effect of the magnetic spring on the whole vibrator is analyzed. The main components are designed, the dynamic model of the part of the vibrator is established, and the factors affecting the displacement of the excited vibration body are obtained; the stiffness of the main components is carried out. The resonance frequency of the vibrator and the displacement of the excited vibrator are measured by the precision impedance analyzer and the laser micrometer. The relationship between the resonance frequency of the excited vibrator and the axial spacing of the magnetic spring is obtained, and the displacement of the central point of the piezoelectric vibrator is compared, and the displacement magnification of the resonant pump vibrator is obtained.
The basic structure and working process of the magnetic spring type resonant pump body are introduced in detail. The diaphragm theory is used to optimize the diaphragm of the pump body, and the structural parameters of the diaphragm are determined. The effect of the volume change rate of the cavity, the flow state and the lag of the valve on the performance of the pump is analyzed in detail, and the test device is designed and measured. Based on the test results, the valve plugging diameter, the width of the cantilever, the height of the chamber and the pretightening height of the valve seat are selected, and the optimum structural parameters of the resonance pump body are finally determined.
The cause of the torsion of the piezoelectric vibrator in the vertical direction is analyzed. Because of the existence of the machining error, the axial stiffness of the magnetic spring in the resonant pump is not quite consistent with the theoretical calculation. The two magnet of the magnetic spring is not completely concentric in the axial direction, which will produce an extra one on the basis of only one axial force in the original. The radial force, the radial force and the axial force will produce the torque to the piezoelectric vibrator connected with the suspension magnet. With the decrease of the axial gap, the radial force becomes larger and the two ring magnet is more and more eccentricity. Therefore, the actual axial stiffness of the magnetic spring is smaller than the theoretical calculation, and the radial stiffness will increase.
The key to the success of the magnetic spring resonance pump lies in the control of the axial stiffness of the magnetic spring, increasing the excitation of the piezoelectric vibrator and improving the utilization efficiency of the piezoelectric vibrator. The control of the axial stiffness of the magnetic spring can draw on the research results obtained by the magnetic levitation train and the magnetic bearing, and the key to increase the excitation of the piezoelectric vibrator is to find out. The piezoelectric ceramics with high quality parameters are made to make the piezoelectric vibrator, and the efficiency of the excitation of the high voltage vibrator must be realized by improving the structure design of the resonant pump.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH38

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