US Patent 10215296 Pressure relief valve tuning feature

A pressure relief valve (10) in a hydraulic tensioner for an endless loop power transmission member and method of assembly can include a check valve member (18) positioned within a fluid passage (14) defined by a housing (12) for movement toward and away from a valve seat (16) defined by the housing (12), a spring (20) normally biasing the check valve member (18) toward the valve seat (16), and a spring retainer (22) assembled within the fluid passage (14) to a variable depth in response to feedback pressure for automatically adjusting a biasing force of the assembled spring (20) to compensate for tolerances effecting a relief pressure value of an assembled pressure relief valve and allowing control of the relief pressure value to be within a predetermined range with respect to a predetermined target relief pressure value for driving the check valve member (18) away from the valve seat (16).