An acoustic insulation structure for a power train according to the present disclosure is provided with a cover member that covers at least an internal combustion engine of the power train including the internal combustion engine, and that includes a pool portion in which water that has entered into the inside of the cover member pools; and a water-absorption member arranged at the inside of the cover member. The cover member includes a moisture outlet that releases, into the atmospheric air, moisture present inside the cover member. The water-absorption member extends to the moisture outlet from the pool portion.

An acoustic insulation system for an internal combustion engine mounted on a vehicle includes: an acoustic insulation cover configured to cover the internal combustion engine with a gap interposed between the acoustic insulation cover and the internal combustion engine. The acoustic insulation cover includes a cover front portion that faces forward of the vehicle. The cover front portion includes: a plurality of inlets for introducing the outside air into the interior of the acoustic insulation cover; and a plurality of inlet flaps configured to respectively open and close the plurality of inlets. The acoustic insulation system further includes a control device configured to control the opening and closing of the plurality of inlet flaps.

An acoustic insulation system for an internal combustion engine mounted on a vehicle includes: an acoustic insulation cover configured to cover the internal combustion engine with a gap interposed between the acoustic insulation cover and the internal combustion engine. The acoustic insulation cover includes a cover front portion that faces forward of the vehicle. The cover front portion includes: a plurality of inlets for introducing the outside air into the interior of the acoustic insulation cover; and a plurality of inlet flaps configured to respectively open and close the plurality of inlets. The acoustic insulation system further includes a control device configured to control the opening and closing of the plurality of inlet flaps.

A soundproof structure includes a porous fibrous body that attenuates incident sound waves, wherein the fibrous body is formed of fibers having an average fiber diameter of 0.5 μm or more and 5 μm or less, and includes a surface layer on which the sound waves are incident and a propagation layer that is stacked with the surface layer and that propagates the sound waves from the surface layer, and wherein the propagation layer includes a high density layer having a density higher than a density of the surface layer.

A soundproof structure includes a porous fibrous body that attenuates incident sound waves, wherein the fibrous body is formed of fibers having an average fiber diameter of 0.5 μm or more and 5 μm or less, and includes a surface layer on which the sound waves are incident and a propagation layer that is stacked with the surface layer and that propagates the sound waves from the surface layer, and wherein the propagation layer includes a high density layer having a density higher than a density of the surface layer.

There is provided a maintenance cover member including: a cover body for closing an opening of a power train of a vehicle; and a vibration suppressing member attached to a surface of the cover body. There is also provided a maintenance cover member including: a cover body for closing an opening of a power train of a vehicle; and a plurality of vibration suppressing members attached to a surface of the cover body. Adjacent vibration suppressing members are disposed spaced apart from each other.

There is provided a maintenance cover member including: a cover body for closing an opening of a power train of a vehicle; and a vibration suppressing member attached to a surface of the cover body. There is also provided a maintenance cover member including: a cover body for closing an opening of a power train of a vehicle; and a plurality of vibration suppressing members attached to a surface of the cover body. Adjacent vibration suppressing members are disposed spaced apart from each other.

Power systems having reduced operating noise and associated methods are disclosed. An example non-synchronous power system includes an engine, a generator, a driveshaft, and a pulley system. The engine may be configured to output, to the driveshaft, a rotational force at a first rotational speed. The pulley system may be configured to receive the rotational force at the first rotational speed at a first pulley and to output the rotational force at a second rotational speed via a second pulley. The first and second pulleys may be drivingly coupled to one another at a fixed pulley ratio. The generator may be configured to receive the rotational force at the second rotational speed to generate electric power.

A connector includes a first buffer member that includes a spiral-shaped wire, a second buffer member that has a substantially annular and flat plate-like shape capable of warping in a thickness direction, a collar member that includes a first flange facing a radially inner side of the first buffer member, and a second flange facing a radially inner side of the second buffer member, and a coupling member. A gap for allowing the second buffer member to move in a radial direction is formed between the second buffer member and a cylindrical portion. A distance between a position of a surface of the second flange and a position of a lowest end of the collar member is greater than a distance between a position of a surface of the first flange and the position of the surface of the second flange in a view in an axial direction.

A connector includes a first buffer member that includes a spiral-shaped wire, a second buffer member that has a substantially annular and flat plate-like shape capable of warping in a thickness direction, a collar member that includes a first flange facing a radially inner side of the first buffer member, and a second flange facing a radially inner side of the second buffer member, and a coupling member. A gap for allowing the second buffer member to move in a radial direction is formed between the second buffer member and a cylindrical portion. A distance between a position of a surface of the second flange and a position of a lowest end of the collar member is greater than a distance between a position of a surface of the first flange and the position of the surface of the second flange in a view in an axial direction.