Patent attributes
A driving force transmission apparatus includes: a motion power transmission part for transmitting a motion power via a driving medium formed by a belt or a chain; and a tensioner for applying a tension to the driving medium. The tensioner includes: a compression spring for biasing the driving medium; a stopper for preventing the compression spring from being compressed to a length less than a predetermined length; and an adjustment part for pushing the compression spring to be the predetermined length in a direction toward the driving medium. According to this configuration, the tension of the driving medium is dominant at installation. When the driving medium becomes fatigue to some extent, the stopper of the tensioner becomes off and the compression spring absorbs the vibration of the driving medium. As a result, the exchange timing of the tensioner can be extended by a simple configuration.
