Solenoid valve design to solve the main problem is the problem of sealing must be through the calculation of electromagnetic force, spring force and gas pressure to ensure that the solenoid valve is cut off gas circuit, when energized to overcome the spring force and gas pressure electromagnetic force quickly open Gas line. At the same time reasonable design of the seal structure, the selection of suitable materials to ensure the solenoid valve in the high temperature (+50 ℃) and low temperature (-20 ℃) ​​environment work properly. 1, the solenoid valve structure design to achieve solenoid valve sealing requirements, we must first ensure that the structure of the main seal knot a reasonable design, easy processing to ensure. Reference to the working principle of the inlet valve, the following improved design. 1.1, the design of the stem Solenoid valve seal is the use of the valve stem at both ends of the cone, respectively, by moving the valve stem seal inlet port and deflation port. This form of sealing requires high precision machining stem, in particular, the concentricity of the stem at both ends of the concentricity requirements within 0.01mm. The two cones with the general CNC machining must be processed separately in the two positioning, cone concentricity requirements is difficult to guarantee, so the performance of the imported solenoid valve in the use of very unstable, short service life, and the domestic traditional electromagnetic Valve can only be used in the low-pressure working range, Figure 2 is the stem schematic. In the design of the solenoid valve, by changing the valve stem structure, the original form of the cone at both ends of the original seal to one end face seal, the other side to keep the cone seal. This cone concentricity and end face of the verticality and beating with ordinary CNC machine tools can be processed in a positioning, the design of the stem is relatively easy to ensure accuracy, while reducing processing costs. Figure 3 is a schematic diagram of stem design. 1.2, the design of sealing force In the solenoid valve design, the introduction of the concept of pneumatic sealing force, that is, by changing the cross-sectional area of ​​both ends of the intake port S1, S2, the section S1> S2, the introduction of high-pressure gas P0, acting on The pressure of the gas in the two sections are: F'1 = P0 · S1 F'2 = P0 · S2 In this way, when both sides of the valve are closed, the pressure difference F'1-F'2 is formed at both ends of the section , Resulting in a pneumatic seal. At this time, the sealing force of the electromagnetic valve when closed is provided by the gas sealing force and the spring force, which not only ensures the sealing force required when the electromagnetic valve is closed, but also reduces the design strength of the spring and prolongs the service life of the spring. 3.2, the theoretical calculation of the solenoid valve 3.2.1, electromagnetic force calculation The design of the solenoid type Ⅲ electromagnet, the specific shape shown in Figure 4. In the magnetic system of the magnetic system, due to the smaller working air gap, so although there is leakage flux, but compared to the main flux can be ignored, so by the "balance of electromagnet design calculation and experimental study," the electromagnet F0 = 275.56 × 103; From the above into the formula (6) was: F = 1848.9N The above calculation results theoretically proved the rationality of the solenoid valve design, while the high-pressure high flow Solenoid valve has been used in a model ground tester, proved to be reliable, stable performance. Its successful development has solved the phenomenon of past product dependence on imports and provided a reference for the development of similar products.