Patent ID: 7967236
Filing Date: 2011-06-28
Classification: B65H

Abstract:
1. An apparatus for attenuating vibration in a roll assembly of a fiber web machine, comprising; a roll in the roll assembly, the roll having a first end, a second end, and a lowest bending eigenfrequency; a first bearing housing supported on a machine frame or foundation via at least one first viscoelastic intermediate piece, wherein the roll is rotatably suspended at the first end on a first bearing in the first bearing housing, and the first bearing housing being supported on the machine frame or foundation; a second bearing housing supported on a machine frame or foundation via at least one second viscoelastic intermediate piece, wherein the roll is rotatably suspended at the second end on a second bearing in the second bearing housing, and the second bearing housing is supported on a machine frame or foundation; wherein the at least one first viscoelastic intermediate piece, and the at least one second viscoelastic intermediate piece have loss factors of greater than 0.1 at a frequency range which is ±10% of the lowest bending eigenfrequency of the roll in normal operation; wherein the at least one first viscoelastic intermediate piece has a spring constant in a range of 0.04 GN/m-1 GN/m; wherein the at least one second viscoelastic intermediate piece have a spring constant in a range of 0.04 GN/m-1 GN/m; wherein the roll has a spring constant k wherein the first end of the roll defines a first shaft journal which contacts the first bearing to define a spring constant k wherein the machine frame or foundation which supports the first bearing housing has a spring constant k wherein the spring constant of the at least one first viscoelastic intermediate piece k wherein the second end of the roll defines a second shaft journal which contacts the second bearing to define a spring constant k wherein the machine frame or foundation which supports the second bearing housing has a spring constant k wherein the spring constant of the at least one second viscoelastic intermediate piece k where