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 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 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 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 pendulum crankshaft for an internal combustion engine includes a pendulum crankshaft having pendulum crank cycloid inserts. The inserts may be formed from high graded hardened steel while the crankshaft may be formed from conventional iron. The pendulum crankshaft includes a crankshaft having pendulum-holding ears. A cycloid insert-receiving aperture is formed in each of said ears for receiving a cycloid insert. Each of the cycloid inserts has a cycloid path formed therethrough. The pendulum is movably attached to the ears by a rolling pin fitted through the cycloid paths of the ears and captured between the cycloid paths formed in each half of the pendulum. Each half of the pendulum includes recessed areas on which the cycloid paths are formed. A pin is provided between each cycloid insert and the ear into which it is inserted to restrict rotation of the cycloid insert with respect to the ear.

A crankshaft comprising a cheek, a torsion-absorbing pendulum pivotally coupled to the cheek, and a rotational speed actuated brake to oppose motion of the pendulum relative to the cheek. The brake is configured to provide greater opposition to the motion at lower rotational speeds than at higher rotational speeds.

A crankshaft assembly for an internal combustion engine can include a crankshaft having a lobe with a pendulum absorber coupled thereto. The pendulum absorber can include a carrier, a pendulum, a pin and a centrifugal switch assembly. The carrier can be coupled to a body of the lobe and can have an opening therein. The pendulum can have an opening therein and the pin can extend through the pendulum opening and the carrier opening to pivotably couple the pendulum to the carrier. The switch assembly can be slidably positioned in a bore of the body and can have a lock member configured to selectively engage the pendulum based on a centrifugal force being below a predetermined threshold to lock movement of the pendulum relative to the carrier.