In order to get the better electromagnetic characteristics of the micro digital valve, the larger electromagnetic force should be obtained in the smaller electromagnetic structure. The electromagnetic force directly determines the electromagnetic properties of the miniature digital valve. The electromagnetic force test is studied in the paper. The results of electromagnetic simulation results are basically consistent with the experimental results. The simulation model is reliable and accurate. The dynamic simulation results show that the dynamic characteristics of the miniature digital valve meet the requirements of the digital hydraulic technology. Design of the new micro digital valve is reasonable.
Digital hydraulics technology has a potential to replace the proportional technology and the servo technology because of their superior properties, such as low cost, reliability, and insensitivity to contamination [
A large number of working mechanisms of electromagnetic characteristics of the high-speed valves have been studied [
According to the above literatures, it can be concluded that electromagnetic force plays a key role in the micro high-speed digital valve. Structure parameters are crucial to the electromagnetic force. Although the researchers have done a lot of research work on electromagnetic force, they only focused on different driving parameters and structure parameters. The objective of this paper is to research electromagnetic characteristics and dynamic response of the new miniature digital valve. The effects of different parameters on magnetic properties and dynamic response are analyzed in the paper.
Unlike the traditional digital valve, the new micro digital valve adopts the spring top arrangement, as shown in Figure
Novel micro high-speed digital valve.
Traditional micro high-speed digital valve.
Accurate simulation models can make our calculation more accurate. In order to verify the accuracy of the model, we have adopted the verification method between experiment and simulation. In the simulation, we use the finite element method in [
Mesh model of the traditional valve.
Mesh model of the novel valve.
Detailed information of Maxwell computation.
Item | Classification | Setting | |
---|---|---|---|
Physical properties | Armature | Material property | DT4 |
Outer diameter | 5 mm | ||
Air gap | 0.1 mm | ||
Coil | Material property | Copper | |
Winding type | Standard | ||
Turns | Variable | ||
Height of coil | 14 mm | ||
Inner diameter of coil | 7.5 mm | ||
Outer diameter of coil | 10 mm | ||
Other components | Material property | Al or 316 L | |
Motion field | Material property | Air | |
Solving domain | Material property | Air | |
Initial boundary | Driven condition | Direct current | Variable |
The testing platform of electromagnetic force was made up of the industrial personal computer, the current controller, the current collector, the control panel, force transducer, and the host computer, as is seen in Figure
Testing platform of electromagnetic force.
Micro high-speed digital valve.
The dynamic and static characteristics of the solenoid valve are related to the magnitude of the electromagnetic force, the greater the electromagnetic force, the better the characteristics of the micro digital valve. Using the electromagnetic force test platform, the test conditions can be adjusted by changing the magnitude of excitation current and air gap stroke. In order to verify the correctness of the simulation model and settings, the electromagnetic force of the miniature digital valve with 0.9 A test current, 400 coil turns, and 0.1 mm air gap stroke is tested. The simulation and test results are shown in Figure
Simulation and testing comparison of electromagnetic force of the two valves.
The characteristics of electromagnetic field determine the magnitude of electromagnetic force. The greater the magnetic field line density of electromagnetic field, the greater is the intensity of electromagnetic field. The variation of magnetic line density and electromagnetic field intensity under different excitation currents is studied in this paper. As shown in Figure
Distribution of magnetic lines of force. (a) 0.8 A. (b) 1.2 A.
Magnetic induction intensity. (a) 0.8 A. (b) 1.2 A.
Energy nephogram. (a) 0.8 A. (b) 0.8 A.
The current rising speed of the electromagnet determines the dynamic characteristics of the micro solenoid valve. The faster the current rising speed, the better the dynamic characteristics. The rising speed of the current depends on the inductance of the electromagnet, and the inductance is related to the number of coils. As shown in Figure
Current under different coil turns.
The motion speed, displacement, and electromagnetic force of different coil loops are shown in Figures
Velocity under different coil turns.
Position under different coil turns.
Electromagnetic force under different coil turns.
In this paper, the simulation results are in good agreement with the experimental results of the miniature digital valve, and the simulation model is accurate. The electromagnetic characteristics and dynamic response are studied in the paper. The smaller the coil number and the smaller the inductance, the faster the current response of the electromagnet. Correspondingly, the faster the speed, the greater the displacement. Therefore, under the same conditions, the coil turns should be reasonably reduced to improve the dynamic characteristics of the micro digital valve.
The data used to support the findings of this study are available from the corresponding author upon request.
The authors declare no conflicts of interest.
This work was supported by the National Natural Science Foundation of China (Nos. U1509204, 51475462, and 91748210).