Nok Corporation

Nobuhiko Narita

Koki Shionuma

A torsional damper is provided having a hub in which a boss adapted to be fixed to a rotating shaft, such as a crankshaft of an engine, and an annular rim are integrally provided via a plurality of stays, and an annular vibration ring connected to an outer circumferential surface of the rim via an elastic body. The stays have a circumferential width dimension that does not exceed one-quarter of the wavelength of the axial resonant frequency of the hub, and are thickened within a range in which the axial thickness dimension does not exceed one-half of the wavelength of the axial resonant frequency of the hub. Thickening of the stays is implemented by, for example, setting the axial thickness dimension thereof to a length equal to or more than one-quarter of the wavelength of the axial resonant frequency of the hub. The stays have an axially inclined shape.

Torsional damper

A grommet is provided including a grommet body made of rubber-like elastic material and to be mounted on a mating component, and a center shaft configured to secure the grommet body on the mating component. The grommet body includes a cylindrical insertion portion to be inserted into a mounting hole formed on the mating component, a folded catcher formed on the leading end of the insertion portion, an umbrella-shaped head formed on the rear end of the insertion portion, and a groove-like release space defined on the inner circumferential surface of the insertion portion. The center shaft includes a shaft to be inserted into the inner circumference of the insertion portion, a folded catcher formed on the leading end of the shaft, and a head formed on the rear end of the shaft.

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Tottori, Japan

Nobuhiko Narita