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).

Friction shaft damper includes springy projections pressing against inside surface of a portion of rotor such as drive shaft with spring force. Central mass may be positioned inside surface of drive shaft by projections extending outwardly from central mass and slideably engaging inside surface of drive shaft. Enlarged section or chamber of shaft may surround and axially trap damper. Axially spaced apart sets of springy fingers may position mass inside shaft and radially inner ends of fingers may be secured to mass and radially outer ends of fingers may be positioned and free to slide along inside surface of shaft. Two axially spaced apart, annular deflection limiters may be placed around mass with small clearances C between deflection limiters and inside surface of shaft. Damper may be a multi-lobed wave spring having multi-lobed rim attached to mass by struts. Damper may be multi-lobed wave spring with crests.

In a method for identifying an unbalance correction for flexible rotors (1), the rotor (1) is rotatably mounted in two bearing devices. An RPM sensor (4) records the speed of the rotor (1) and a radial movement of the rotor (1) is recorded, by means of position sensors (3) at measuring points (6), during an unbalance measurement run or a plurality of unbalance measurement runs for different rotor speeds. The measured values recorded are fed to an evaluation device (5), which determines the eccentricity measured values assigned to the measuring points (6) by means of expanding the influence coefficient method, and therefore unbalances are determined per plane and eccentricities are determined per measuring point for each measurement run.

Turbochargers operate at extremely high speed, so balance of the rotating core is of the utmost importance to turbocharger life. A special balancing washer is added to the clamping region between the compressor nut and the nose of the compressor wheel to aid in keeping the wheel, nut, and stub-shaft on the turbocharger axis and to thereby prevent introduction of core unbalance.

A balancing weight mountable within a balance hole of a rotary component includes a cylindrical body having a desired weight. An opening is formed in a portion of the body to define a hollow passageway and a mechanism couples the cylindrical body within an interior of the balance hole.

A drive shaft assembly includes an elongate member and a tuned absorber assembly. The elongate member has an exterior surface that is disposed about an axis. The tuned absorber assembly includes a mass and a sleeve. The mass is at least partially disposed about the exterior surface. The sleeve extends between a first sleeve end and a second sleeve end. The sleeve is disposed about the mass and spaces the mass apart from the exterior surface of the elongate member.

To provide an electric motor enabling easy and high-precision balance correction, and a machine toll including this electric motor. An electric motor (1) includes: a cylindrical stator (2); a rotor (3) having a rotary shaft part (31) inserted inside of the stator (2); a housing (4) installed to both ends in an axial direction of the stator (2); an opening (51a) provided in at least one outer peripheral lateral face of the housing (4), and disposed to be separated from an internal space (S) of the stator and a ventilation passage (9) formed in the stator (2); and a balance correction component (6, 61) that is installed to the rotary shaft part (31), and corrects balance of the rotor (3), in which the balance correction component (61) is exposed to outside from the opening (51a); and a machine tool (10) includes this electric motor (1).

A method for forming a shaft assembly includes: providing a shaft structure, the shaft structure comprising a shaft and a universal joint member that is coupled to an end of the shaft; inserting a weight member to the shaft structure to form an intermediate assembly, the weight member being formed at least partly from a liquid resin, the intermediate assembly having an initial rotational unbalance; rotating the intermediate assembly about a longitudinal axis of the shaft structure to re-distribute a least a portion of the weight member circumferentially about the shaft structure to at least partly attenuate the initial rotational unbalance; and curing the liquid resin while rotating the intermediate assembly to fix the re-distributed portion of the weight member to the shaft structure to thereby form a balance weight that at least partly attenuates the initial rotational unbalance. A shaft assembly is also provided.

Disclosed is a gas turbine engine rotor balancing apparatus comprising: a rotor configured to rotate about a rotor axis; a substantially annular balancing mass configured to encircle the rotor; and a mass adjustment apparatus for adjusting the position of the balancing mass relative to the rotor.

A bearing that rotatably supports a rotating shaft includes an inner wheel that supports the rotating shaft in a manner to be coaxial with the rotating shaft; an outer wheel provided radially outside the inner wheel; and a plurality of rolling bodies that are provided in a ring-shaped gap between the inner wheel and the outer wheel. The inner wheel is provided with a correcting section that corrects eccentric rotation of the rotating shaft.