RECIPROCATING ROTARY MECHANISM OF ENGINE AND METHOD FOR MANUFACTURING THE SAME

To effectively reduce noise generated during engine operation in a reciprocating rotary mechanism of an engine in which first and second dynamic vibration absorbers are provided to a piston or a connecting rod.SOLUTION: A resonance frequency of a second dynamic vibration absorber 82 is higher than a resonance frequency of a first dynamic vibration absorber 81. At least one of a ratio of a mass of a mass part 83a of the first dynamic vibration absorber 81 to a reciprocating inertial mass of a reciprocating rotary mechanism and a ratio of a mass of a mass part 83b of the second dynamic vibration absorber 82 to the reciprocating inertial mass of the reciprocating rotary mechanism is set so that an antiresonance peak frequency that appears at a higher-frequency side of the resonance frequency of the first dynamic vibration absorber 81 has a substantially different value from an antiresonance peak frequency that appears at a lower-frequency side of the resonance frequency of the second dynamic vibration absorber 82.SELECTED DRAWING: Figure 4 【課題】ピストンまたはコンロッドに第１、第２動吸振器が設けられたエンジンの往復回転機構において、エンジンの運転中に生じる騒音を効果的に低減する。【解決手段】第２動吸振器８２の共振周波数は、第１動吸振器８１の共振周波数よりも高い。往復回転機構の往復慣性質量に対する第１動吸振器８１の質量部８３ａの質量の比、および、往復回転機構の往復慣性質量に対する第２動吸振器８２の質量部８３ｂの質量の比の少なくとも一方は、第１動吸振器８１の共振周波数の高周波数側に出現する反共振のピーク周波数が、第２動吸振器８２の共振周波数の低周波数側に出現する反共振のピーク周波数と実質的に異なる値を有するように設定されている。【選択図】図４