流体脉宽调制双向变量机构流量特性研究OA北大核心CSTPCD

The method of variable-speed driving variable pump is mostly adopted for the bidirectional flow changes of hydraulic system.However,the structure of variable mechanism is relatively complicated,and frequent bidirectional variable regulation will lead to low dynamic response speed.Therefore,a new mechanism for flow regulation of fixed displacement pump was proposed to realize bidirectional variable function.The duty cycle of fluid pulse width modulation was changed by the axial movement of the spool of bidirectional variable mechanism.The product of the rotating speed of the spool relative to the valve sleeve and the number of valve port on the spool determined the frequency of fluid pulse width modulation.The flow characteristics of the bidirectional variable mechanism were analyzed by simulation and test.The results showed that the bidirectional variable mechanism could achieve bidirectional flow control with duty cycle of 0 to 100%,ane there was only 1.8%deviation between the simulation and test results.The research results provide a new flow control method for hydraulic pump with fixed speed design to use under variable speed working condition.