摘要
研制一种基于液压微位移放大结构的压电陶瓷直接驱动伺服阀,实现大流量高频响的要求。针对压电陶瓷输出力大但输出位移小的特点,设计出一种新型的液压微位移放大结构,由柔性铰链膜片式大活塞、密闭容腔、小活塞及压力调节和测量装置构成。采用叠堆式压电陶瓷驱动大活塞,改变密闭容腔内油液的体积形态,放大小活塞端输出位移,驱动滑阀阀芯运动。大活塞采用膜片结构,降低压电陶瓷叠堆的负载,提高密封性能。针对刚性膜片刚度和强度矛盾的问题,设计柔性铰链膜片,对该膜片结构的刚度进行理论分析和数值计算验证。应用有限元方法对结构及各参数进行优化设计,并对最终结构进行刚度和强度分析。基于试制原理样机参数,建模仿真表明液压位移放大倍数9倍,阀芯位置控制误差小于1%。频宽超过550 Hz。试验测得流量曲线,7 MPa压力下,控制流量达到17 L/min。
A servo valve direct driven by piezoelectric actuator using hydraulic amplification is researched. It takes advantage of the higher bandwidth and larger flow rate. A new hydraulic displacement amplifier structure is proposed to aim at the smaller displacement output and larger force output of piezoelectric（PZT）. The structure is composed of input piston with larger area, output piston with smaller area and hermetic chamber. The larger stroke multilayer piezoelectric actuator is served as the drive element that drives the input piston with larger area of the hydraulic amplification. The change of pressure and volume drives the output piston directly connected to the spool to produce amplified displacement, which drive the spool to move. To satisfy the demand of sealing and low load, a diaphragm with flexure hinge structure is used for the piston with larger area. The structure and parameter is optimized by finite element method. Piezoelectric direct drive servo valve prototype is trial-manufactured and tested. The simulation results show that the displacement magnification times is 9, the governing error of valve spool is less than 1%, the bandwidth is up to 550 Hz. The flow curve obtained by experiment show the flow rate can reach to 17 L/min at pressure of 7 MPa.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2013年第2期151-158,共8页
Journal of Mechanical Engineering
基金
国家杰出青年科学基金资助项目(50825502)
关键词
压电陶瓷
液压位移放大
直接驱动阀
柔性铰链
有限元法
Piezoelectric ceramic Hydraulic amplification Direct drive servo-valve Flexure hinge Finite element method
