Hydraulic damping mechanism and use for belt tensioning

A hydraulic damper for providing fluid damping to a tensioner in a drive system comprising:

• a damper cup having an open end and a closed end, wherein the damper cup is operatively associated with a tensioner arm and configured to rotate about a central axle in tandem with the tensioner arm;
• an end plate having a central opening, sealingly engaged with the open end of the damper cup to form a fluid chamber;
• a damping fluid within the fluid chamber;
• a plurality of shear plates housed within the fluid chamber, the plurality of shear plates comprising alternating fixed plates engaged with a fixed component of the tensioner and rotatable plates engaged with a rotatable component of the tensioner;
• and
• a connecting member extending from said end plate toward said closed end of said damper cup;
• wherein the fixed plates each have at least one opening positioned between a central opening therein and an outer edge thereof;
• wherein the rotatable plates each have at least one opening positioned between a central opening therein and an outer edge thereon;
• wherein the opening in each of the fixed plates unalignedly, overlaps the opening in an adjacent rotatable plate;
• wherein at least one of said fixed plates includes an elongate opening that defines a range of rotation for said connecting member in both a winding direction and a tensioning direction that is less than 360 degrees, the connecting member being received in said elongate opening.

A method of hydraulically damping a tensioner in a drive system comprising:

• providing a tensioner having a damper cup having an open end and a closed end, wherein the damper cup is operatively associated with a tensioner arm and configured to rotate about a central axle in tandem with the tensioner arm;
• providing an end plate having a connecting member extending therefrom;
• mounting a plurality of shear plates on the central axle within said damper cup, the plurality of shear plates comprising alternating fixed plates engaged with a fixed component of the tensioner and rotatable plates engaged with a rotatable component of the tensioner, wherein at least one of the fixed plates has an elongate opening that defines a range of rotation of the connecting member relative to the fixed plate of less than 360 degrees in both a winding direction and a tensioning direction;
• sealing and closing the damper cup's open end with the end plate, wherein the connecting member passes through the rotatable plates and is received in the elongate opening of the at least one fixed plate;
• and
• filling the fluid chamber with a damping fluid.