Regulator

A regulator comprising:

• a main body part including a tubular path with a first open end and a second open end, wherein the first open end in the tubular path formed through the main body part is an inlet port of fluid and the second open end is an outlet port of pressure-reduced fluid;
• a pressure regulation chamber arranged on an inner side of the inlet port in the tubular path through a valve seat including a valve seated seat holding member which includes a valve seated seat on an inner side and in which a through hole in an axial direction of the tubular path is formed, a piston pressure regulating valve including a pressure regulating valve body that has a leading end surface capable of being in contact with the valve seated seat and that includes a tubular communicating path with first and second open ends;
• a piston unit formed around an outer periphery of a side of the outlet port in the tubular path, of the pressure regulating valve body is biased in an outlet port direction in the tubular path between the pressure regulation chamber and the outlet port in the tubular path by a pressure regulating spring having a predetermined load and arranged slidably in the axial direction of the tubular path in an atmosphere chamber provided coaxially in parallel with the pressure regulation chamber around the piston unit, wherein fluid is regulated to an intended pressure by controlling of fluid pressure in the pressure regulation chamber by a change in opening areas of the valve seated seat and the pressure regulating valve body due to balancing between a load by pressure of fluid that is introduced from the inlet port, is introduced into the valve seated seat and the pressure regulation chamber, which is provided in such a manner as to face the valve seated seat, through the through hole formed in the valve seated seat holding member of the pressure regulating valve body, passes through the pressure regulating valve body in which the communicating path is formed, and affects the piston unit joined to the pressure regulating valve body, wherein a load by the pressure regulating spring that affects the piston unit to an opposite side of the pressure regulation chamber is extracted from the outlet port, wherein the pressure regulating valve body is in contact with the valve seated seat at a contact location, and the piston unit that is formed around the outer periphery thereof and that affects the pressure regulating spring are formed separately, the two forming the piston pressure regulating valve, and the pressure regulating valve body inserted from the inlet port into the tubular path and the piston unit inserted from the outlet port into the tubular path are fit to each other in an intended axial direction position and subsequently fixed by at least one of press-fitting and welding, and wherein the pressure regulating body includes an inner peripheral leading end, on a side of the valve seated seat, having a tapered portion that is enlarged toward a leading end direction;
• and a fuel airtight seal, wherein the contact location and the fuel airtight seal have an equivalent diameter, the fuel airtight seal is configured to fit between an inner peripheral surface of the tubular path and the outer periphery of the pressure regulating valve body, the inner peripheral surface is arranged to face the valve seated seat, and the valve seated seat includes an outer peripheral edge having a rounded contact region relative to the pressure regulating valve body.