Abstract: A support member 10 having a tubular portion 11 is joined at an end portion of a muffler pipe 1. The support member 10 forms a flange 12 as a valve seat and a support bracket 14. The support bracket 14 has a valve disk 20 supported rotatably via a hinge axis 15. The valve disk 20 has an outer peripheral portion 12 as a contact surface with the valve seat, and a weight 30 is welded to a bead portion 23 with an inner portion thereof projecting to the back face. A spring is wound around the hinge axis, with one end 18 engaging a back face of the valve wall 21 for the valve disk, the other end engaging a support bracket. The resonance frequency is decreased by the weight, thereby preventing the beat sound from arising in a normal range of the engine speed. The weight is welded to the bead portion, thereby not causing the outer peripheral portion 23 as the contact surface to be distorted.

Abstract: A valve seat structure is secured to an outlet end of a passing pipe installed in an exhaust muffler. The valve seat structure includes a flat seat surface portion which extends around the outlet end of the passing pipe. A valve plate structure is pivotally connected to the valve seat structure. The valve plate structure includes a valve plate portion and a flat sealing portion which forms a peripheral part of the valve plate portion. The valve plate structure has a close position wherein the valve plate portion closes the outlet end of the passing pipe having the flat sealing portion entirely pressed against the flat seat surface of the valve seat structure and an open position wherein the valve plate portion opens the outlet end of the passing pipe having the flat sealing portion separated from the flat seat surface. A biasing structure biases the valve plate structure to assume the close position.

Abstract: A valve for a control muffler includes: a valve element which is swingably journaled on a support shaft 5 supported by shaft holes 41a of a pair of first shaft supporting portions 41 inside the support shaft 5; bushes 6 which are respectively interposed between the support shaft 5 and a pair of second shaft supporting portions 33 that are disposed on the valve element to pivotally support the support shaft 5; and a coil spring which urges the valve element in a valve closing direction. In the valve, a welding rising portion 41b which protrudes in the axial direction is disposed on an outer opening edge of the shaft hole 41a of each of the pair of first shaft supporting portions 41, and the support shaft 5 is welded to tip ends of the welding rising portion 41b.

Abstract: A support member 10 having a tubular portion 11 is joined at an end portion of a muffler pipe 1. The support member 10 forms a flange 12 as a valve seat and a support bracket 14. The support bracket 14 has a valve disk 20 supported rotatably via a hinge axis 15. The valve disk 20 has an outer peripheral portion 12 as a contact surface with the valve seat, and a weight 30 is welded to a bead portion 23 with an inner portion thereof projecting to the back face. A spring is wound around the hinge axis, with one end 18 engaging a back face of the valve wall 21 for the valve disk, the other end engaging a support bracket. The resonance frequency is decreased by the weight, thereby preventing the beat sound from arising in a normal range of the engine speed. The weight is welded to the bead portion, thereby not causing the outer peripheral portion 23 as the contact surface to be distorted.

Abstract: A valve for a control muffler includes: a valve element which is swingably journaled on a support shaft 5 supported by shaft holes 41a of a pair of first shaft supporting portions 41 inside the support shaft 5; bushes 6 which are respectively interposed between the support shaft 5 and a pair of second shaft supporting portions 33 that are disposed on the valve element to pivotally support the support shaft 5; and a coil spring which urges the valve element in a valve closing direction. In the valve, a welding rising portion 41b which protrudes in the axial direction is disposed on an outer opening edge of the shaft hole 41a of each of the pair of first shaft supporting portions 41, and the support shaft 5 is welded to tip ends of the welding rising portion 41b.

Abstract: A valve seat structure is secured to an outlet end of a passing pipe installed in an exhaust muffler. The valve seat structure includes a flat seat surface portion which extends around the outlet end of the passing pipe. A valve plate structure is pivotally connected to the valve seat structure. The valve plate structure includes a valve plate portion and a flat sealing portion which forms a peripheral part of the valve plate portion. The valve plate structure has a close position wherein the valve plate portion closes the outlet end of the passing pipe having the flat sealing portion entirely pressed against the flat seat surface of the valve seat structure and an open position wherein the valve plate portion opens the outlet end of the passing pipe having the flat sealing portion separated from the flat seat surface. A biasing structure biases the valve plate structure to assume the close position.