Design and Parametric Analysis of the Constant Force Characteristics of the Electromagnet for Hydraulic Valves

The electromagnet is the most used driving device for hydraulic valves; especially the proportional electromagnet with constant force characteristics is the basis for the excellent control performance of hydraulic valves. However, the constant force characteristics of the proportional electromagnet are related to many parameters and are difficult to obtain. In view of the above problems, this paper designs a proportional electromagnet for driving hydraulic valves with the goal of constant force characteristics, with the minimum variance of the output electromagnetic force in the working range as the condition. Firstly, this paper introduces the working principle of proportional electromagnets and establishes the model of electromagnetic force. Then, the influences of the basin bottom radius, the guide angle width and the basin mouth depth on the constant force characteristics of the electromagnet were studied by the finite element method (FEM). Their values are found respectively to give the electromagnet constant force characteristics. Finally, the test bench of the electromagnet was built, and its constant force characteristics and output characteristics were continuously tested. The results show that the test results of the output electromagnet force are highly consistent with the simulation results and have constant force characteristics. Related research deepens the understanding of how the key parameters affect the constant force characteristics, and helps designers optimize these parameters to develop new structures, which have certain practical engineering values.