US Patent 11181088 Internal-combustion engine starting device

An internal-combustion engine starting device includes a switch section, a motor section, a transmission mechanism section, and a pinion gear section, wherein the transmission mechanism section is configured of a planetary gear train including a pinion which is connected to the rotating shaft of the motor section, a plurality of planetary gears to which the rotation of the pinion is transmitted, and an internal gear which receives the rotation of the planetary gears; and of a machine casing in which is housed the planetary gear train, and wherein elastic bodies are each fitted between a protruding portion formed on the outer peripheral surface of the internal gear and a recessed portion in which to receive the protruding portion, and clearances are formed between the internal gear and the machine casing via the elastic bodies.