| 摘要 |
A belt tensioner ( 20 ) for a belt drive ( 1 ) is designed to connect an engine shaft ( 6 ) of an internal-combustion engine ( 2 ) to a reversible electric machine ( 4 ) which has the function of starting motor and current generator, the belt tensioner ( 20 ) comprises a fixed part ( 21 ) and a pair of arms ( 23, 24 ), hinged on a common pin ( 31 ) carried by the fixed part ( 21 ) and provided with respective idle pulleys ( 25, 26 ), and a spring ( 27 ), which forces the two arms ( 23, 24 ) towards one another so as to load the pulleys ( 25, 26 ) elastically against respective branches ( 15 a, 15 b) of the belt ( 15 ). The two arms ( 23, 24 ) of the belt tensioner are provided with respective first arrest elements ( 37, 47 ), which are designed to interact with the fixed portion ( 21 ) to define respective positions of arrest of the arms themselves under the action of the spring ( 27 ), and respective second arrest elements ( 38, 48 ), which are designed to interact with the fixed portion ( 21 ) to define respective positions of end-of travel of the arms ( 23, 24 ) under the action of the pull of the belt ( 15 ).
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