Valve seat assembly, proportional electromagnetic valve and breathing machine

The utility model discloses a valve seat assembly, a proportional electromagnetic valve and a breathing machine, and the valve seat assembly comprises a valve seat, a valve core, a moving armature, an elastic sheet and a pressing piece; an air inlet channel and an installation cavity are formed in the valve seat, one end of the air inlet channel is an air inlet, the other end of the air inlet channel communicates with the installation cavity, an air outlet is formed in the cavity wall of the installation cavity, and an opening is formed in the end, away from the air inlet channel, of the installation cavity. The valve element is arranged in the mounting cavity and blocks the end, away from the air inlet, of the air inlet channel, and a limiting groove is formed in the outer periphery of the valve element. One end of the moving armature penetrates through the valve element and extends to the air inlet channel, and the other end of the moving armature extends towards the opening direction of the mounting cavity