Marine engines and balance shaft arrangements for marine engines

摘要

A balance shaft arrangement is for a marine engine having a crankshaft supported for rotation about a crankshaft axis and a drive gear supported for rotation with the crankshaft. The balancing arrangement has at least one balance shaft, and a driven gear being driven into rotation by the drive gear, the driven gear being connected to the balance shaft so as to drive the balance shaft into rotation. The driven gear is selectively radially positionable towards and away from the drive gear. A dampening member is disposed between the driven gear and the balance shaft, the dampening member accommodating radial positioning of the driven gear with respect to the balance shaft.

主权项

1. A marine engine, comprising:
a crankshaft that is supported for rotation about a crankshaft axis; a drive gear that rotates with the crankshaft; a balance shaft that is supported for rotation so as to balance secondary vibrational forces of the crankshaft; a driven gear that causes rotation of the balance shaft; wherein said drive gear causes rotation of the driven gear and wherein the driven gear is selectively radially movable towards and away from the drive gear about an eccentric axis; a cylinder that supports the driven gear, the cylinder comprising an outer circumferential surface and an inner circumferential surface that is eccentrically aligned with respect to the outer circumferential surface, wherein rotation of the cylinder in one direction moves the driven gear towards the drive gear and wherein rotation of the cylinder in an opposite direction moves the driven gear away from the drive gear; and a support plate coupled to the cylinder, wherein rotation of the support plate causes rotation of the cylinder.