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.

A trim balance device for a gas turbine engine having a rotatable shaft extending along a central longitudinal axis of the gas turbine engine includes a trim balance nut that is at least partially disposed about the rotatable shaft. The trim balance nut defines an aperture that extends from a first trim balance nut end towards a second trim balance nut end along the central longitudinal axis. The aperture being arranged to receive and seat a balance weight.

A composite drive shaft damper includes both foamed and non-foamed NVH-reducing materials to dampen particular NVH-causing frequencies within a drive shaft.

A propeller shaft (1) that is a power transmission shaft has a shaft member (2) as a tubular body made of iron-based metal and a balance weight (3) made of iron-based metal and welded to an outer peripheral surface of this shaft member (2). At least a part of the balance weight (3) of the propeller shaft (1) is covered with a sacrificial metal coating (4) made of sacrificial corrosion prevention material that contains metal whose ionization tendency is higher than that of metal forming the shaft member (2). With this, it is possible to suppress local progression of corrosion at a periphery of the balance weight (3) and improve durability of the propeller shaft (1).

A center bearing assembly for a multi-piece propeller shaft includes a stud yoke extending along an axis A between first and second stud yoke ends to define a central stub shaft rotatable about the axis A. A rotatable weld collar is operably connected to the second stud yoke end of the central stub shaft for simultaneous rotation therewith. The rotatable weld collar includes a body extending from a first collar end disposed adjacent the central stub shaft to a second collar end to define an exterior surface. A tuned damper extends radially outwardly from the exterior surface of the rotatable weld collar for reducing noise, vibration, and/or harshness (NVH) generated during operation of the multi-piece propeller shaft. A first shaft segment is operably connected to the rotatable weld collar and a second shaft segment is operably connected to the stud yoke for transferring a rotational force therebetween.

An example method of balancing a shaft includes inserting a balancing insert into one of a plurality of cavities. The plurality of cavities are radially inside an outermost surface of the shaft.

A method for dynamically balancing an unbalanced article about a rotary axis. The method includes determining a mass and a position of a corrective weight, the mass and position of the corrective weight being configured to at least partly correct an imbalance in the unbalanced article that is generated when the unbalanced article is rotated about the rotary axis; and spraying an atomized liquid or molten material toward a surface of the unbalanced article to form the corrective weight.

A center bearing assembly for a multi-piece propeller shaft includes a stud yoke extending along an axis A between first and second stud yoke ends to define a central stub shaft rotatable about the axis A. A rotatable weld collar is operably connected to the second stud yoke end of the central stub shaft for simultaneous rotation therewith. The rotatable weld collar includes a body extending from a first collar end disposed adjacent the central stub shaft to a second collar end to define an exterior surface. A tuned damper extends radially outwardly from the exterior surface of the rotatable weld collar for reducing noise, vibration, and/or harshness (NVH) generated during operation of the multi-piece propeller shaft. A first shaft segment is operably connected to the rotatable weld collar and a second shaft segment is operably connected to the stud yoke for transferring a rotational force therebetween.

In a method for determining an equivalent modal unbalance for the first bending characteristic form of a shaft-elastic rotor, which unbalance is to be compensated for, a rotor model is created describing the geometric shape and material properties of the shaft-elastic rotor. The magnitude of compliance of the rotor model is calculated at a measurement point and at the center of gravity of the rotor at an assumed speed. The shaft-elastic rotor is received in a rotatable bearing and accelerated to the assumed speed which is below its first critical speed. Subsequently, the magnitude of outward deflection at the measurement point of the shaft-elastic rotor rotating at the assumed speed can be measured. The equivalent modal unbalance for the first bending characteristic form of the shaft-elastic rotor, which unbalance is to be compensated for, can be calculated from the magnitudes of the calculated compliance and the measured outward deflection.

A balance device for an internal combustion engine includes a crankshaft and a balance shaft. The crankshaft includes a CS eccentric weight. The balance shaft includes a BS eccentric weight. A CS connected point deviated from the CS main shaft, and a BS connected point deviated from the BS axial shaft are connected with a connection rod. A CS connection mechanism that enables relative rotation of the crankshaft and the connection rod is provided at the CS connected point. A BS connection mechanism that enables relative rotation of the balance shaft and the connection rod is provided at the BS connected point. A guide section guides a motion of the connection rod so that the balance shaft rotates in an opposite direction to the crankshaft.