EGR valve including seal ring

An EGR valve configured to be mounted on an engine of an automobile and to open and close an EGR passage to recirculate a part of exhaust gas in an exhaust passage of the engine therethrough to an intake passage of the engine, comprising:

• a housing having a nozzle forming a part of the EGR passage;
• a shaft rotatably supported by the housing;
• a butterfly valve fixed to an end of the shaft and configured to open and close the EGR passage;
• and
• a seal ring provided on an outer peripheral edge of the butterfly valve and configured to close a gap between the butterfly valve and an inner peripheral wall of the nozzle when the butterfly valve is fully closed, wherein
• the seal ring is fitted in an annular groove formed over an entirety of the outer peripheral edge of the butterfly valve, wherein
• the seal ring includes:
• a body in an annular shape and including an abutment joint at a location in a circumferential direction, wherein
• opposite ends of the body form the abutment joint and include an overlapping part where a first end and a second end of the body overlap each other,
• the overlapping part includes a step cut joint that forms an overlap in a radial direction and a lap joint that forms an overlap in a plate thickness direction,
• facing faces that face each other in the plate thickness direction in the lap joint are planes extending from an inner peripheral circular arc of the seal ring up to an outer peripheral circular arc of the seal ring, wherein
• the first end includes a first locking piece and a first locked piece,
• the second end includes a second locking piece and a second locked piece,
• the first locking piece is a projection that extends in a circumferential direction on an outer diameter side of the first end,
• the second locking piece is a projection that extends in the circumferential direction on an outer diameter side of the second end,
• the first locked piece is a step that extends in the circumferential direction on an inner diameter side of the first end,
• the second locked piece is a step that extends in the circumferential direction on an inner diameter side of the second end,
• the first locking piece and the first locked piece overlap with each other in the radial direction to form the step cut joint, and
• the second locking piece and the second locked piece face each other in the plate thickness direction to form the lap joint.