A torsional damper is provided with: a hub affixed to a rotary shaft and having an outer-circumferential surface along a circle centered on the rotary shaft; an annular oscillation ring having an inner-circumferential surface the diameter of which is larger than the outer-circumferential surface of the hub on a circle centered on the rotary shaft; and a rubber ring that exists in a compressed state between the outer-circumferential surface of the hub and the inner-circumferential surface of the oscillation ring, comprises a rubber composition the main component of which is EPDM, and has a loss coefficient (tan δ) of 0.18 or higher when the surface temperature is 60±5° C. When subjected to resonance point tracking, the fitting diameter (d) and the maximum attained surface temperature (Tmax) of the rubber ring during continuous excitation at the resonance point satisfy a prescribed relational expression.

A torsional damper is provided with: a hub affixed to a rotary shaft and having an outer-circumferential surface along a circle centered on the rotary shaft; an annular oscillation ring having an inner-circumferential surface the diameter of which is larger than the outer-circumferential surface of the hub on a circle centered on the rotary shaft; and a rubber ring that exists in a compressed state between the outer-circumferential surface of the hub and the inner-circumferential surface of the oscillation ring, comprises a rubber composition the main component of which is EPDM, and has a loss coefficient (tan δ) of 0.18 or higher when the surface temperature is 60±5° C. When subjected to resonance point tracking, the fitting diameter (d) and the maximum attained surface temperature (Tmax) of the rubber ring during continuous excitation at the resonance point satisfy a prescribed relational expression.

A brake assembly for an electric motor includes: a magnetic body, a winding, a bolt, a housing part with a brake surface, an armature disk, a brake pad plate, a shaft, a spring part, and a first bushing. The housing part is connected to the magnetic body by the bolt, with a positive fit in at least the circumferential direction. The first bushing is accommodated in a second bushing. The spring part supported on the housing part presses the first bushing and/or the second bushing toward the magnetic body. The radial clearance range covered by the armature disk includes the radial clearance range covered by the second bushing, and the axial region covered by the armature disk includes the axial region covered by the second bushing.

A brake assembly for an electric motor includes: a magnetic body, a winding, a bolt, a housing part with a brake surface, an armature disk, a brake pad plate, a shaft, a spring part, and a first bushing. The housing part is connected to the magnetic body by the bolt, with a positive fit in at least the circumferential direction. The first bushing is accommodated in a second bushing. The spring part supported on the housing part presses the first bushing and/or the second bushing toward the magnetic body. The radial clearance range covered by the armature disk includes the radial clearance range covered by the second bushing, and the axial region covered by the armature disk includes the axial region covered by the second bushing.

In a multi-stage torsional coupling and associated methods of providing variable stiffness, the coupling has an inner member connected to a first torsional connection, a sprocket plate connected to the inner member, one or more plates connected to a second torsional connection, an outer member rigidly attached to the one or more plates, and a plurality of damping stages arranged for sequential engagement by movement of the sprocket plate relative to the one or more plates to provide a variable stiffness over a angle of angular displacement for the multi-stage torsional coupling. The sprocket plate is rotatable relative to the one or more plates to sequentially engage the plurality of damping stages to provide stiffness between the first and second torsional connections that increases in a non-linear, or stepped, manner as the amplitude of the angular displacement of the sprocket plate relative to the one or more plates increases.

Torsional vibration dampers (TVDs) having a plurality of spokes that are asymmetric by having a changing spoke thickness in the angular direction with the greatest thickness at the position where the belt torque and the dynamic torque of the TVD act in unison are disclosed. The spokes, which connect a central member to a peripheral rim, include an asymmetrical thickness in an angular direction, as evidenced by a cross-section view transverse to a radial length of each of the plurality of spokes. Engine systems having one of the disclosed TVDs mounted to a shaft are also disclosed, for example a TVD mounted to a crankshaft.

A sealing structure that allows for formation of a side lip, as well as a labyrinth structure between an oil seal and a torsional vibration damper, even when a reinforcing ring has a short inward flange part. The sealing body 120 includes a side lip 124 extending from near a distal end of an inward flange part 112 of the reinforcing ring 110 radially inward and further toward an air side (A) than a dust lip 122 to a position not as far as the outer circumferential surface of a tubular part 210. The tubular part 210 includes a small-diameter part 211 on which the dust lip 122 slides, and a large-diameter part 212 on the air side (A). The large-diameter part 212 has a tapered surface 212a formed on an outer circumferential surface thereof that reduces in diameter toward the air side (A). An annular gap S is formed between this tapered surface 212a and an inner circumferential surface of the side lip 124.

A sealing structure that allows for formation of a side lip, as well as a labyrinth structure between an oil seal and a torsional vibration damper, even when a reinforcing ring has a short inward flange part. The sealing body 120 includes a side lip 124 extending from near a distal end of an inward flange part 112 of the reinforcing ring 110 radially inward and further toward an air side (A) than a dust lip 122 to a position not as far as the outer circumferential surface of a tubular part 210. The tubular part 210 includes a small-diameter part 211 on which the dust lip 122 slides, and a large-diameter part 212 on the air side (A). The large-diameter part 212 has a tapered surface 212a formed on an outer circumferential surface thereof that reduces in diameter toward the air side (A). An annular gap S is formed between this tapered surface 212a and an inner circumferential surface of the side lip 124.

Torsional vibration dampers are disclosed that have a hub defining a plurality of fastener-receiving openings and an inertia member concentric about and spaced a radial distance apart from a shaft-receiving member of the hub and having a plurality of receptacles defining a bore oriented axially. Each receptacle aligns with one of the plurality of fastener-receiving openings, and receives one of a plurality of elastomeric rings with a fastener seated therein and received in the fastener-receiving openings to operatively connect the inertia member to the hub through compression of the elastomeric rings. The height of each elastomeric ring is greater than the axial width of the receptacles, and compression of the elastomeric rings deforms each radially into a first gap between the hub and the inertia member and a second gap between the inertia member and the fastener, thereby axially locking the inertia member to the hub for rotation together.

A sealing structure allows for formation of a side lip, as well as a labyrinth structure between an oil seal and a torsional vibration damper, even when a reinforcing ring has a short inward flange part. The sealing body 120 includes a side lip 124 extending from near a distal end of an inward flange part 112 radially inward and further toward an air side (A) than a dust lip 122 to a position not as far as the outer circumferential surface of a tubular part 210. An annular member 250 is further provided, which is fixed to the outer circumferential surface of the tubular part 210 further on the air side (A) than the side lip 124 and covering an outer circumferential surface of the side lip 124 such that there is a gap between the annular member 250 itself and the outer circumferential surface of the side lip 124.