초록 ▼

A support member10having a tubular portion11is joined at an end portion of a muffler pipe1. The support member10forms a flange12as a valve seat and a support bracket14. The support bracket14has a valve disk20supported rotatably via a hinge axis15. The valve disk20has an outer peripheral portion12as

A support member10having a tubular portion11is joined at an end portion of a muffler pipe1. The support member10forms a flange12as a valve seat and a support bracket14. The support bracket14has a valve disk20supported rotatably via a hinge axis15. The valve disk20has an outer peripheral portion12as a contact surface with the valve seat, and a weight30is welded to a bead portion23with an inner portion thereof projecting to the back face. A spring is wound around the hinge axis, with one end18engaging a back face of the valve wall21for 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 portion23as the contact surface to be distorted.

대표청구항 ▼

1. A valve structure for an engine exhaust system, comprising: a valve disk attached to an exhaust pipe, the valve disk being opened or closed in accordance with an exhaust pressure in the exhaust pipe, the valve disk comprises: a valve wall having a contact surface to abut with a valve seat of t

1. A valve structure for an engine exhaust system, comprising: a valve disk attached to an exhaust pipe, the valve disk being opened or closed in accordance with an exhaust pressure in the exhaust pipe, the valve disk comprises: a valve wall having a contact surface to abut with a valve seat of the exhaust pipe; anda convex portion; a spring for biasing the valve disk to close the exhaust pipe; a rotation shaft for rotatably supporting the valve disk; and a weight fixed to the convex portion. 2. The valve structure according to claim 1, wherein the valve wall of the valve disk is defined around the convex portion.3. The valve structure according to claim 2, wherein the convex portion projects from a back surface of the valve disk opposed to the contact surface of the valve wall; and the weight is fixed to the convex portion on the back surface of the valve wall. 4. The valve structure according to claim 1, wherein the spring is wound around the rotation shaft; one end of the spring engages the back surface of the valve wall; and the weight is fixed on the back surface of the valve wall except for an engagement point with the one end of the spring. 5. A valve structure for an engine exhaust system, comprising: a valve disk attached to an exhaust pipe, the valve disk being opened or closed in accordance with an exhaust pressure in the exhaust pipe, the valve disk comprising a valve wall defined on an outer peripheral edge of the valve disk, the valve disk having a contact surface to abut with a valve seat of the exhaust pipe; and a spring for biasing the valve disk to close the exhaust pipe; a rotation shaft for rotatably supporting the valve disk; and a weight formed of a circular arc and fixed on a back surface of the valve disk, the weight disposed along an arcuate portion of the valve wall most left away from the rotation shaft. 6. The valve structure according to claim 5, wherein the valve disk comprises a flange formed around the outer periphery of the valve wall; and the weight is disposed along the inside of the flange and welded to the flange. 7. The valve structure according to claim 6, wherein the flange includes a projection piece, and the weight is welded at the tip of the projection piece.8. The valve structure according to claim 5, wherein the valve disc comprises: a flange having a holding piece, the flange formed around the outer periphery of the valve wall; a convex portion projects from a back surface of the valve disk opposed to the contact surface of the valve wall; and the weight is disposed between the flange and the convex portion along inside of the flange; and the holding piece of the flange presses the weight to be caulked and fixed to the valve wall. 9. The valve structure for the engine exhaust system according to claim 5, wherein the weight is formed by cutting the strip steel plate.10. The valve structure according to claim 5, wherein the weight is formed by bending a steel material having a predetermined cross section.