초록 ▼

A variable ratio drive pulley of the type employed in snowmobiles to transmit a drive from the snowmobile engine to a variable ratio belt drive transmission has a fixed flange and an opposed movable flange which cooperate to drive the belt. The drive pulley is coupled to rotate with the engine crank

A variable ratio drive pulley of the type employed in snowmobiles to transmit a drive from the snowmobile engine to a variable ratio belt drive transmission has a fixed flange and an opposed movable flange which cooperate to drive the belt. The drive pulley is coupled to rotate with the engine crankshaft and the movable flange incorporates centrifugal weights that operate to advance it towards the fixed flange, with a force that increases with speed of rotation to grip the transmission belt between the flanges and apply a driving torque thereto, this torque being applied by both the flanges. To reduce the effects of engine induced vibrations on the centrifugal weights and on the movable flange, a damping structure is incorporated in the torque path between the engine crankshaft and the centrifugal weights and movable flange. The damping structure comprises a hexagonal rubber ring that is positioned between a driving head and the hub of the drive pulley to absorb vibrations which would otherwise be transmitted between these.

대표청구항 ▼

A variable ratio drive pulley comprising: a) a shaft; b) confronting fixed and movable frusto-conical flanges mounted on said shaft to rotate therewith, said fixed flange being fixed to said shaft and said movable flange being guided to move axially of said shaft towards and away from said fixed fla

A variable ratio drive pulley comprising: a) a shaft; b) confronting fixed and movable frusto-conical flanges mounted on said shaft to rotate therewith, said fixed flange being fixed to said shaft and said movable flange being guided to move axially of said shaft towards and away from said fixed flange; c) a spring in said pulley being operative to urge said movable flange away from said fixed flange; d) a centrifugally responsive mechanism in said pulley being operative on rotation of said pulley to generate a force urging said movable flange towards said fixed flange, such force increasing with the rotational speed of said pulley; e) a torque transmitter for transmitting a driving torque from said shaft to said movable flange, said torque transmitter comprising an operating head assembly fixed to rotate with said shaft, said head assembly including a plurality of radial driving arms equiangularly spaced about the axis of said shaft, said driving arms engaging abutment surfaces on said movable flange at a radial spacing from said shaft axis to deliver driving torque to said movable flange; f) said head assembly and said movable flange having cooperating axially extending guide surfaces by which said movable flange is guided from movement axially of said shaft; g) said head assembly being connected to said shaft through a damping element said damping element being operative to attenuate transmission of torsional vibrations from said shaft to said movable flange.