Belt tensioner with frustoconical pivot bearing

Abstract

A belt tensioner in which the bearing for mounting the pulley carrying pivoted structure on the fixed structure comprises a frustoconical sleeve bearing having a frustoconical exterior surface and a frustoconical interior surface engaged between annular portions of the two structures. The frustoconical surface of one of the annular portions is (1) formed on the exterior periphery thereof and (2) disposed in engagement with the interior bearing frustoconical surface. The one annular portion has a load center point disposed on the pivotal axis of the pivoted structure. The other annular portion has a load center point disposed on a line disposed within a plane passing through the pivotal axis of the pivoted structure and the rotational axis of the pulley corresponding to the one line of the two lines of intersection of the bearing frustoconical surface with the plane through which the radially inward force component transmitted by the pivoted structure is applied to the sleeve bearing. The load center points are positioned such that the radially inward force component transmitted by the pivoted structure and resisted by the fixed structure is transmitted generally from one load center point to the other along a line extending between the points which line is perpendicular to and bisects the one line so that the radially inward force component transmitted by the pivoted structure to the sleeve bearing is distributed evenly throughout the axial extent of the sleeve bearing.