Endless drive arrangement for hybrid vehicle using two-armed tensioner with non-orbiting arms

An endless drive arrangement, comprising:

• a crankshaft pulley that is driveable by an engine;
• an auxiliary power device, having an auxiliary power device pulley that is rotatable about an auxiliary power device pulley axis, wherein the auxiliary power device pulley is provided on an auxiliary power device drive shaft that extends from an end-face of the auxiliary power device, wherein the end-face is part of a frame for the auxiliary power device;
• an endless drive member that extends about the crankshaft pulley and the auxiliary power device pulley;
• and
• a tensioner that includes
• a base that is mountable to a frame of an auxiliary power device having an auxiliary power device pulley that is rotatable about an auxiliary power device pulley axis;
• a first arm having a first tensioner pulley, wherein the first arm is pivotally mounted to the base at a first arm pivot structure;
• a second arm having a second tensioner pulley, wherein the second arm is pivotally mounted to the base at a second arm pivot structure;
• and
• an arm biasing member operably connected to the first arm and the second arm;
• wherein the first and second tensioner pulleys are positioned to engage first and second spans respectively of the endless drive member on first and second sides of the auxiliary power device pulley, and
• wherein the first tensioner pulley and the second tensioner pulley are moveable along a first selected path and a second selected path respectively, and the first and second selected paths are positioned such that, for any combination of tensions in the first and second spans within the selected range of tensions the first tensioner pulley and the second tensioner pulley remain sufficiently spaced apart from one another that the first and second spans of the endless drive member remain spaced apart from one another,
• wherein the first arm and the second arm are positionable during use to hold the first and second spans in such a way that a radial line extending from the auxiliary power device pulley axis passes through the first and second spans.

A tensioner for maintaining tension in an endless drive member that is drivable by an engine and that engages an auxiliary power device pulley that is mounted to an auxiliary power device drive shaft extending from a frame of an auxiliary power device, the tensioner comprising:

• a base that is mountable to the frame of an auxiliary power device;
• a first arm having a first tensioner pulley, wherein the first arm is pivotally mounted to the base at a first arm pivot structure;
• a second arm having a second tensioner pulley, wherein the second arm is pivotally mounted to the base at a second arm pivot structure;
• and
• an arm biasing member operably connected to the first arm and the second arm;
• wherein the first and second tensioner pulleys are positioned to engage first and second spans respectively of the endless drive member on first and second sides of the auxiliary power device pulley,
• wherein the first span is at a lower tension than the second span when the auxiliary power device is not supplying power to the engine via the endless drive member and wherein the second span is at a lower tension than the first span when the auxiliary power device is supplying power to the engine via the endless drive member, and
• wherein the first tensioner pulley and the second tensioner pulley are moveable along a first selected path and a second selected path respectively, and the first and second selected paths are positioned such that, for any combination of tensions in the first and second spans within the selected range of tensions the first tensioner pulley and the second tensioner pulley remain sufficiently spaced apart from one another that the first and second spans of the endless drive member remain spaced apart from one another,
• wherein the first tensioner pulley axis is at a first arm pivot distance from a pivot axis of the first arm pivot structure, and wherein the second tensioner pulley axis is at a second arm pivot distance from a pivot axis of the second arm pivot structure, wherein the first arm pivot distance is greater than the second arm pivot distance.