Exhaust valve device

Abstract

An exhaust valve device includes a valve body, a valve seat, a support shaft, a coil spring, and a cushion member. The valve body is placed in an exhaust passage in a silencer, and configured to open and close the exhaust passage. The valve body abuts against the valve seat when the valve body is closed. The support shaft is fixed to the valve seat, and supports the valve body to be able to swing freely. The support shaft is inserted in the coil spring. The coil spring biases the valve body. The cushion member is interposed between the coil spring and the support shaft. The cushion member is rotatable relative to the support shaft.

1 . An exhaust valve device comprising:
 a valve body placed in an exhaust passage in a silencer, and configured to open and close the exhaust passage;   a valve seat against which the valve body abuts when the valve body is closed;   a support shaft fixed to the valve seat, and supporting the valve body to be able to swing freely;   a coil spring in which the support shaft is inserted, the coil spring biasing the valve body; and   a cushion member interposed between the coil spring and the support shaft, the cushion member being rotatable relative to the support shaft.   
     
     
         2 . The exhaust valve device of  claim 1 , wherein
 the cushion member is shorter than the support shaft, and interposed between the coil spring and the support shaft at one end part in an axial direction of the coil spring, at which the coil spring abuts the valve body.   
     
     
         3 . The exhaust valve device of  claim 1 , wherein
 the cushion member is placed between a part of the coil spring that biases the valve body, and the support shaft, and is provided integrally with the valve body, and   when opening and closing the valve body, the cushion member swings together with the valve body.   
     
     
         4 . The exhaust valve device of  claim 3 , wherein
 the cushion member is spaced apart from the support shaft by a prescribed clearance.   
     
     
         5 . The exhaust valve device of  claim 3 , wherein
 the cushion member is integrated with the valve body.   
     
     
         6 . The exhaust valve device of  claim 5 , wherein
 the cushion member includes a cylindrical part in which the support shaft is inserted, and a flange part that is welded to the valve body.   
     
     
         7 . The exhaust valve device of  claim 5 , wherein
 the cushion member includes a semi-cylindrical part in which the support shaft is inserted, and a flange part that is welded to the valve body.   
     
     
         8 . The exhaust valve device of  claim 3 , wherein
 the cushion member is formed integrally with the valve body.   
     
     
         9 . The exhaust valve device of  claim 1 , further comprising
 an additional cushion member interposed between the coil spring and the support shaft, the additional cushion member being rotatable relative to the support shaft, wherein   each of the cushion member and the additional cushion member is cylindrical.   
     
     
         10 . The exhaust valve device of  claim 9 , wherein
 one of the cushion member and the additional cushion member is provided between a part at which the coil spring biases the valve body, and the support shaft.   
     
     
         11 . The exhaust valve device of  claim 9 , wherein
 each of the cushion member and the additional cushion member is spaced apart from the support shaft by a prescribed clearance.