Balance shaft having reduced mass and inertia
AssigneeAmerican Axle & Manufacturing, Inc.
InventorsStephen A. Clark, John C. Geis, Carl E. Holmblad, Craig Lawrence McEachran
Life of this patent
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Abstract
A balance weight having one or more journals with a reduced mass portion disposed between a pair of journal portions that define circumferentially extending bearing surfaces. The reduced mass portion has a body, which defines a circumferentially extending bearing surface that is concentric with the bearing surfaces on the journal portions, and at least one stiffening structure that is configured to resist flexing of the journal portions relative to one another due to the transmission of bending loads through the balance shaft.
Claims21
A balance shaft having first and second journals and at least one counterweight, the first and second journals defining a rotational axis, the at least one counterweight being fixedly coupled to the first and second journals;
- wherein the first journal defines a first journal portion, a second journal portion and a reduced mass portion disposed along the rotational axis between the first and second journal portions, the first journal portion defining a first circumferentially extending bearing surface, the second journal portion defining a second circumferentially extending bearing surface,
- the reduced mass portion having a body and a stiffening structure that are both disposed axially along the rotational axis between the first and second circumferentially extending bearing surfaces, the body being fixedly coupled to the first and second journal portions and defining a third circumferentially extending bearing surface that is concentric with the first and second circumferentially extending bearing surfaces, the stiffening structure intersecting the body and the first and second journal portions and terminating radially inwardly of the first circumferentially extending bearing surface such that a void space is disposed between the first and second journal portions at a location that is radially outwardly of the stiffening structure;
- wherein the stiffening structure defines a first pocket, which is disposed adjacent the first journal portion, and a second pocket, which is disposed adjacent the second journal portion, and wherein the first and second pockets are spaced apart from one another along the rotational axis to form a land there between, and wherein the land and the first and second pockets are disposed along the rotational axis between edges of the first and second circumferentially extending bearing surfaces that are closest to one another such that the first pocket is between the land and the first journal portion and the second pocket is between the land and the second journal portion.
A balance shaft having first and second journals and at least one counterweight, the first and second journals defining a rotational axis, the at least one counterweight being fixedly coupled to the first and second journals;
- wherein the first journal defines a first journal portion, a second journal portion and a reduced mass portion disposed along the rotational axis between the first and second journal portions, the first journal portion defining a first circumferentially extending bearing surface, the second journal portion defining a second circumferentially extending bearing surface,
- the reduced mass portion having a body and a stiffening structure that are both disposed axially between the first and second circumferentially extending bearing surfaces, the body being fixedly coupled to the first and second journal portions and at least partly defining a third circumferentially extending bearing surface that is concentric with the first and second circumferentially extending bearing surfaces, the stiffening structure being fixedly coupled to the first and second journal portions and terminating radially inwardly of the first circumferentially extending bearing surface such that a void space is disposed between the first and second journal portions at a location that is radially outwardly of the stiffening structure;
- wherein in a cross-section of the balance shaft taken perpendicular to the rotational axis, the void space extends between the rotational axis and the body.
Dependencies are inferred from the claim text.