A coaxial liquid pressure regulator, comprising: - a housing defining a longitudinal axis and having an inlet portion and an outlet portion; - a substantially tubular valve member slidingly accommodated inside said housing and having a longitudinal axial passage and an upstream end with an inlet edge for the liquid; - a valve body fixed inside said inlet portion defining a seat configured to interact with said inlet edge of said valve member and form therewith a port having a variable width; wherein said inlet portion comprises an inlet fitting for connection to a liquid supply line, and a collection chamber directly downstream of said inlet fitting, said collection chamber defines a diametral geometric plane (Ω) which passes through said longitudinal axis; wherein said valve body comprises a cantilever element transversely extending from the inner wall of said collection chamber; wherein first deflection means and second deflection means are successively arranged between said inlet fitting and said inlet edge to facilitate flow conveyance toward said port and said longitudinal passage; wherein said first deflection means comprise a pair of struts for bracing the connection of said cantilever element to the inner wall of said chamber; wherein said struts extend along planes (π, Ψ) substantially parallel to said longitudinal axis and symmetrically spaced apart from said diametral geometric plane (Ω), characterized in that said extension planes (π, Ψ) form a lateral deflection angle (α) with said geometric plane (Ω) to facilitate flow conveyance on opposite sides from said diametral geometric plane (Ω), an annular insert being designed to be positioned on the bottom of said chamber and has an inner lateral wall, said second deflection means comprising a plurality of deflecting slides formed on the inner wall of the annular insert and is arranged on the periphery of said cantilever element, said plurality of deflecting slides being oriented toward the center of said chamber to convey the liquid toward said port and impart a rotating vortex motion to the flow. - a housing defining a longitudinal axis and having an inlet portion and an outlet portion; - a substantially tubular valve member slidingly accommodated inside said housing and having a longitudinal axial passage and an upstream end with an inlet edge for the liquid; - a valve body fixed inside said inlet portion defining a seat configured to interact with said inlet edge of said valve member and form therewith a port having a variable width; wherein said inlet portion comprises an inlet fitting for connection to a liquid supply line, and a collection chamber directly downstream of said inlet fitting, said collection chamber defines a diametral geometric plane (Ω) which passes through said longitudinal axis; wherein said valve body comprises a cantilever element transversely extending from the inner wall of said collection chamber; wherein first deflection means and second deflection means are successively arranged between said inlet fitting and said inlet edge to facilitate flow conveyance toward said port and said longitudinal passage; wherein said first deflection means comprise a pair of struts for bracing the connection of said cantilever element to the inner wall of said chamber; wherein said struts extend along planes (π, Ψ) substantially parallel to said longitudinal axis and symmetrically spaced apart from said diametral geometric plane (Ω), characterized in that said extension planes (π, Ψ) form a lateral deflection angle (α) with said geometric plane (Ω) to facilitate flow conveyance on opposite sides from said diametral geometric plane (Ω), an annular insert being designed to be positioned on the bottom of said chamber and has an inner lateral wall, said second deflection means comprising a plurality of deflecting slides formed on the inner wall of the annular insert and is arranged on the periphery of said cantilever element, said plurality of deflecting slides being oriented toward the center of said chamber to convey the liquid toward said port and impart a rotating vortex motion to the flow.