Gear control system for vibration attenuation
A power take off unit includes an input gear, an output gear, and an intermediary gear that cooperate to transfer power from a rotational power source to an operating target. The power take off unit has a control module that biases the intermediary gear relative to the input gear and the output gear to reduce gear rattle vibrations associated with intermeshed tooth looseness.
1 . A power take off unit that is adapted to be rotationally driven by a primary drive component and to rotationally drive an auxiliary device, the power take off unit comprising:
a housing that is configured to be attached to a primary drive component;
a first gear that is supported on the housing and includes a portion that extends from the housing and is adapted to be rotationally driven about a first rotational centerline by the primary drive component;
a second gear that is supported on the housing so as to be rotationally driven about a second rotational centerline by the first gear, the second gear adapted to rotationally drive an auxiliary device; and
a biasing mechanism that is responsive to an operating condition of the power take off unit to exert a biasing force that urges one of the first and the second rotational centerlines to move relative to the other of the first and second rotational centerlines such that a positional relationship between the first gear and the second gear is changed to attenuate gear rattle when the power take off unit is operated in a generally unloaded or lightly loaded operating condition.
2 . The power take off unit defined in claim 1 wherein the biasing mechanism includes a control module that is configured to displace the one of the first and the second rotational centerlines relative to the other of the first and second rotational centerlines.
3 . The power take off unit defined in claim 2 wherein the control module includes a spring that exerts a biasing force to displace the one of the first and the second rotational centerlines relative to the other of the first and second rotational centerlines.
4 . The power take off unit defined in claim 1 wherein the first gear is supported on a first shaft, the second gear is supported on a second shaft, and the biasing mechanism is configured to displace one of the first and the second shafts relative to the other of the first and second rotational shafts.