EXHAUST PIPE OPENING/CLOSING VALVE DEVICE

摘要

PROBLEM TO BE SOLVED: To improve rustproof property a low cost. SOLUTION: An inner peripheral hole 2a of a valve housing 2 provided in mid-way of an exhaust pipe of an engine composes a part of the exhaust pipe. A butterfly type valve element 12 is fixed to a rotary shaft 4 supported by axial holes 2b and 2c of the housing 2 by crossing the inner peripheral hole 2a. A lever 20 is fixed to one end of the rotary shaft 4 and a clevis 18 is fixed to a tip of an output rod 14 of an actuator 16. A connecting pin 22 is inserted into a pin insertion hole provided on the lever 20 and the clevis 18 to relatively rotatably connect the rotary shaft 4 and the output rod 14. Electroless nickel plating is imparted to the inner peripheral hole 2a and the axial holes 2b and 2c, and microcrack type hard chrome plating is imparted to the upper layer. Thickness of all the plate layers is determined for above 30μ. The material of the housing 2 is made spherical graphite cast iron. A corrosion resistance gas soft nitriding processing is performed for the pin insertion hole and the connecting pin 22 of the lever 20 and the clevis 18.