Abstract
Due to the influence of material characteristics and winding power, single output electromagnet has limited ability to improve the dynamic characteristic of electro-hydraulic valve. Therefore, an electromechanical converter with double push rods is proposed in this paper, which can simultaneously output two electromagnetic forces, can push or pull the valve core and sleeve according to the current direction and realize rapid operation of load. According to the electromagnetic principle and the magnetic circuit analysis method, the mathematical model and equivalent circuit of the electromechanical converter with double push rods are established. Through the finite element simulation model of the electromechanical converter with double push rods with the same magnetization directions, the changing rules of its magnetic field distribution and force–displacement behaviors are studied and analyzed. According to the analysis results, the electromagnetic mechanical parameters and mechanical structure of the electromechanical converter with double push rods are determined, and the prototype is made. The test platform for the push-pull characteristics of the electromechanical converter with double push rods is built, and its static and dynamic characteristics are tested and analyzed. The results show that the thrust and pull output characteristics of the internal and external push rods are basically consistent with the simulation output, and proportional to the current density of the coil; the push-pull hysteresis of internal and external push rods output force is less than 5%; and the dynamic time response characteristics of the displacement and force are obtained. The hysteresis effect of output force is improved effectively through the H bridge drive control circuit modulated by PWM. Compared with the displacement response of a single-winding electromagnet with a similar volume, it can effectively improve the dynamic displacement response. Follow-up work will further optimize the structure of the electromechanical converter and test the corresponding pilot valve. The research results provide a new theory for improving the output characteristics of electro-hydraulic pilot valve and have an extremely high engineering application value and broad application prospect.
Highlights
In recent years, electro-hydraulic proportional valves have been widely used due to their simple structure, stable performance, high energy efficiency, and eco-friendliness [1,2,3]
Cheng et al [18] designed the corresponding magnetic circuit based on the application of soft magnetic alloy material
Its key part consists of three linear electromagnetic valves, so that it can obtain a large electromagnetic force in a short time [19]
Summary
Electro-hydraulic proportional valves have been widely used due to their simple structure, stable performance, high energy efficiency, and eco-friendliness [1,2,3]. Other studies optimized structural design or the dynamic characteristics of electromagnetic valve by selecting soft magnetic materials with different B–H curves [13,14,15,16]. Wang et al [17] used AL-Fe material to prove by experiment that new soft magnetic material could significantly improve the performance of high-speed electromagnetic digital valve. The electromechanical conversion element composed of PTZ has a high precision and a high response speed, but due to disadvantages such as relatively big hysteresis, the need to develop the corresponding compensation power supply, a small displacement and a high cost, currently the level of commercialization is not high [20, 21]. In order to improve the dynamic response characteristics of the displacement of the electromechanical converter, this paper proposed a new type of electromechanical converter with double push rods and analyzed and studied its dynamic and static characteristics
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