A shaft assembly that includes a shaft, which has a wall with an interior surface, a universal joint member, which is coupled to an end of the shaft and a balance weight that is received in the shaft and fixedly coupled to the interior surface. The balance weight includes an ultraviolet light-curable or light-cured resin.

A balance ring for a gas turbine engine has a ring shaped body with a first radial thickness, an anti-rotation tab extending outward from the body and at least one millable balancing feature connected to the body.

A propeller shaft assembly includes a propeller shaft extending along an axis between a first and second shaft ends. A propeller shaft yoke, such as a slip yoke, stud yoke, or flange yoke, is operably connected to one of said first or second shaft ends. The propeller shaft yoke includes a body between from a first and second yoke end and presenting a mounting surface. A tuned damper extends radially outwardly from the mounting surface to define a first damper side disposed adjacent the first yoke end and a second damper side disposed adjacent the second yoke end. A protective shoulder extends radially outwardly from the mounting surface in spaced and covering relationship with one of the first or second damper sides for protecting the tuned damper from axial forces originating from a respective first or second yoke end of the propeller shaft yoke.

A system and method for controlling rotor dynamics at a rotor assembly is provided. The system includes a magnetic actuator and a controller. The magnetic actuator is positioned in magnetic communication with the rotor assembly and is configured to obtain a measurement vector corresponding to the rotor assembly and a measurement vector indicative of a rotor dynamics parameter. The magnetic actuator is further configured to selectively output an electromagnetic force at the rotor assembly. The controller is configured to store and execute instructions. The instructions include outputting, via the magnetic actuator, a baseline electromagnetic force to the rotor assembly; obtaining the measurement vector at the rotor assembly from the magnetic actuator; determining non-synchronous vibrations corresponding to the rotor assembly based at least on the measurement vector and a rotor speed of the rotor assembly; determining cross coupled stiffness corresponding to the rotor assembly based at least on the measurement vector, the rotor speed, and a predetermined rotor dynamics model of the rotor assembly; determining an adjusted electromagnetic force of the rotor assembly based at least on the cross coupled stiffness and a damping factor corresponding to the electromagnetic force output from the magnetic actuator; and generating an output signal corresponding to the adjusted electromagnetic force to the rotor assembly.

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 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.

An apparatus for correcting an imbalance in a rotating shaft and a method for correcting the imbalance in a rotating shaft is identified. The joint assembly includes a first joint member that is drivingly connected to at least a portion of second joint member via one or more torque transmission elements. At least a portion of a first shaft is drivingly connected to at least a portion of a first joint member and at least a portion of a second shaft is drivingly connected to at least a portion of a second end portion of the second joint member. A boot can is connected to at least a portion of a first end portion of the second joint member and one or more balancing elements are attached to at least a portion of the boot can.

An oscillating power tool with an electric motor is provided, including an armature shaft with an armature and a fan wheel, including an eccentric arranged on the armature shaft at one end thereof, a first balancing mass for balancing an unbalance of the eccentric and possibly an eccentric bearing, being arranged in the proximity of the eccentric or the eccentric bearing, respectively, however, at an axial distance, further including a second balancing mass for balancing a couple unbalance caused by the axial distance between the eccentric and the eccentric bearing, respectively, and the first balancing weight, wherein the second balancing mass is arranged on the armature shaft at the side facing away from the eccentric or the eccentric bearing. Also a method for balancing such an electric motor is provided.

Driveshaft dampers are provided for use in driveshafts to dampen or attenuate aspects of noise, vibration, and harshness (NVH). Systems and methods for making and using driveshaft dampers are further provided. The driveshaft dampers may be made using a helical-winding process and include attenuation strips with elongate protrusions. Various embodiments of helically-wound driveshaft dampers include a core and one or more attenuation strips helically wound around the core.

An oscillating power tool with an electric motor is provided, including an armature shaft with an armature and a fan wheel, including an eccentric arranged on the armature shaft at one end thereof, a first balancing mass for balancing an unbalance of the eccentric and possibly an eccentric bearing, being arranged in the proximity of the eccentric or the eccentric bearing, respectively, however, at an axial distance, further including a second balancing mass for balancing a couple unbalance caused by the axial distance between the eccentric and the eccentric bearing, respectively, and the first balancing weight, wherein the second balancing mass is arranged on the armature shaft at the side facing away from the eccentric or the eccentric bearing. Also a method for balancing such an electric motor is provided.