Patent ID: 7712482

Claim:
A pressure-reducing valve comprising: a housing provided with a primary port and a secondary port; a pressure-reducing piston displaceably retained in an interior of the housing, the pressure-reducing piston being displaced to control an opening degree of the primary port and being configured to separate the interior of the housing into a primary-pressure space connected to the primary port and a secondary-pressure space connected to the secondary port; a driving piston displaceably retained in the interior of the housing, the driving piston being displaced to cause the pressure-reducing piston to be displaced in association therewith and having a secondary-pressure receiving surface that receives a secondary pressure from a fluid in the secondary-pressure space; a spring mechanism configured to exert a spring force against the secondary pressure to at least one of the pressure-reducing piston and the driving piston; a rod displaceably inserted into the pressure-reducing piston and being configured to form a back-pressure space kept at a primary pressure between the rod and the pressure-reducing piston with the rod inserted into the pressure-reducing piston; and a base rod retained in the housing, for applying a pressing force against the primary pressure applied to the rod to support the rod.