Valve assembly having a predetermined shear line

摘要

A valve assembly is disposed between an accumulator and a pressure chamber in a hydraulic brake booster. The valve assembly operates to communicate the pressurized fluid to the pressure chamber when the pressurized fluid within the pressure chamber is insufficient to provide a power assist during braking. The valve assembly comprises a base which is received within a housing separating the accumulator from the pressure chamber. The base defines an opening leading to the housing bore and a body extends into the opening to define a clearance between the base and the body. The clearance leads to a recess on one end of the body which cooperates with a recess on the other end of the body to define a shear line for the body. The body is cut out on the one end of the body adjacent the recess to define a secondary passage and a portion of the body is movable after shearing into engagement with the base to substantially take up the clearance. The cutout cooperates with the base to define a restriction for the secondary passage which communicates the accumulator with the pressure chamber.