Pressure relief valve and method of manufacturing the same

A valve flap assembly for a pressure relief valve having a housing defining at least one interior passage, the assembly comprising:

• a flap carrier frame formed of a first relatively rigid plastic material and having a plurality of perimeter walls, the frame securable to the housing to surround the passage such that the perimeter walls are adjacent edges of the passage;
• a flap formed of a second relatively pliable plastic material and having a hinge edge co-molded into connection with a first of the perimeter walls, the flap bendable about a line adjacent the hinge edge;
• and
• at least one flap stiffener co-molded into connection with the flap.

A one-way pressure relief valve for use in an automotive vehicle comprising:

• a housing defining at least one interior passage and having a valve seat surrounding a periphery of the passage;
• a flap carrier frame formed of a first relatively rigid plastic material separate from the frame and secured to the housing to surround the passage, the frame having first and second spaced, generally parallel perimeter walls extending adjacent respective opposite edges of the passage;
• and
• a flap formed of a second relatively pliable plastic material and having a hinge edge co-molded into connection with the first perimeter wall of the frame and depending therefrom such that the flap contacts the valve seat of the passage and is bendable adjacent the hinge edge allowing the flap to move away from the valve seat.

A one-way pressure relief valve for use in an automotive vehicle comprising:

• a housing defining at least one interior passage and having a valve seat surrounding a periphery of the passage;
• a flap carrier frame formed of a first relatively rigid plastic material and secured to the housing to surround the passage, the frame having first and second spaced, generally parallel perimeter walls extending adjacent respective opposite edges of the passage;
• a flap formed of a second relatively pliable plastic material and having a hinge edge co-molded into connection with the first perimeter wall of the frame and depending therefrom such that the flap contacts the valve seat of the passage and is bendable adjacent the hinge edge so that the flap may move away from the valve seat;
• and
• at least one flap stiffener co-molded into connection with the flap.

A method of forming a pressure relief valve comprising the steps of:

• forming a valve housing defining at least one internal passage;
• in a first shot of a two-shot co-molding process, injection molding a flap carrier frame and at least one flap stiffener from a first relatively rigid plastic material, the flap stiffener comprising a first segment extending generally parallel to an edge of the frame and a second segment extending generally perpendicular to the first segment;
• in a second shot of the co-molding process, injection molding at least one flap from a second relatively flexible plastic material, the flap having a edge contacting the flap carrier frame to join the flap to the flap carrier frame, and the flap contacting the stiffener and joined thereto;
• and
• securing the flap carrier frame to the valve housing to position the flap over the internal passage.