Three-stage pilot inverse proportional pressure-reducing solenoid valve

A three-stage pilot inverse proportional pressure-reducing solenoid valve, comprising a yoke and a stop iron assembly, wherein:

• the yoke is annular, two ends of the yoke are respectively provided with a valve body assembly and a coil assembly, and a first cavity is formed among the valve body assembly, the yoke and the coil assembly;
• the valve body assembly comprises an annular valve body, a primary valve core assembly and a main spring, wherein the valve body is radially provided with a plurality of first radial through holes being evenly distributed on a circumference;
• the primary valve core assembly comprises a valve seat, a primary valve core and a leaf spring being sequentially arranged in the valve body from outside to inside along an axial direction;
• the main spring is arranged between the leaf spring and the primary valve core;
• the valve seat and the primary valve core are respectively provided with a valve seat through hole and a second damping hole being sequentially communicated;
• radial cross-sectional area of the valve seat through hole is larger than radial cross-sectional area of the second damping hole, and the radial cross-sectional area of the second damping hole is smaller than the radial cross-sectional area of the first damping hole;
• the first pilot cavity is sequentially communicated with the outside through the second damping hole and the valve seat through hole;
• the stop iron assembly comprises a stop iron and a small spring;
• the stop iron is located in the first cavity, a flow passage gap is arranged between an outer sidewall of one end, close to the valve body, of the stop iron and an inner wall of the first cavity, a first axial blind hole with an opening facing the valve body is arranged on the stop iron in an axial direction, and a second-stage valve core, a third-stage valve core and an armature are sequentially arranged in the first axial blind hole from outside to inside along an axial direction;
• the second-stage valve core comprises an annular guide cylinder, a first radial outer convex ring arranged on an outer sidewall of the guide cylinder, and a radial inner convex ring arranged on an inner sidewall of one end, close to the valve body assembly, of the guide cylinder, and an inner hole of the radial inner convex ring forms a first damping hole;
• the third-stage valve core comprises an annular ejector rod, a second radial outer convex ring arranged on an outer sidewall of the ejector rod, and a plurality of second radial through holes arranged on a sidewall of one end, close to the second-stage valve core, of the ejector rod, and one end of the ejector rod extends into the guide cylinder and is limited by the radial inner convex ring of the guide cylinder, an outer diameter of the ejector rod is matched with an inner diameter of the guide cylinder and the ejector rod is capable of relatively sliding to block the plurality of second radial through holes, and an other end of the ejector rod is sequentially sleeved with a bearing and a pole shoe from inside to outside in a radial direction, and the other end is used for abutting against the armature;
• a plurality of first axial through holes being evenly distributed on a circumference are arranged on the second radial outer convex ring along an axial direction;
• an inner wall of the first axial blind hole is provided with a first annular groove and a second annular groove being respectively adapted to peripheries of the first radial outer convex ring and the second radial outer convex ring;
• a sidewall of the second annular groove is provided with a plurality of third radial through holes being evenly distributed on a circumference along a radial direction;
• an inner wall of the valve body, the primary valve core assembly and the second-stage valve core forms a first pilot cavity, and the main spring is located in the first pilot cavity;
• a cavity between an inner wall of the guide cylinder and an inner wall of the ejector rod, and among the armature, an outer wall of the ejector rod, the pole shoe, the bearing and an inner wall of the first axial blind hole forms a second pilot cavity;
• the second-stage valve core, the third-stage valve core and an inner wall of the first axial blind hole form an annular third pilot cavity, and the small spring is located in the third pilot cavity;
• the first pilot cavity communicates with an outside through a flow passage on the primary valve core assembly, the first pilot cavity communicates with the second pilot cavity through the first damping hole, and the second pilot cavity communicates with the third pilot cavity through the second radial through holes;
• the third pilot cavity sequentially communicates with the outside through the plurality of first axial through holes, the second annular groove, the plurality of third radial through holes and the flow passage gap, or sequentially through a gap between the second radial outer convex ring and an inner wall of the first axial blind hole, the second annular groove and the plurality of third radial through holes, and the flow passage gap;
• a minimum value of flow passage radial cross-sectional area of the primary valve core assembly is smaller than radial cross-sectional area of the first damping hole, and the radial cross-sectional area of the first damping hole is smaller than sum of radial cross-sectional areas of the plurality of third radial through holes.