Overrunning alternator pulley
Encyclopedia
During normal operation alternator pulleys can rotate at up to 18,000rpm and coupled with rapid acceleration and deceleration can lead to premature alternator
, pulley
and drive belt failure. To prevent this Overrunning Alternator Pulleys (OAPs) were developed that are designed to decouple the alternator from the rotational irregularities of the crankshaft in an internal combustion engine, as the alternator has the highest mass moment of inertia in the accessory belt drive. As a result of this decoupling the alternator is only driven using the acceleration components of the rotational irregularity of the crankshaft.
The overrunning alternator pulley consists of a pulley, an overrunning clutch unit with a double bearing support, a drawn inner ring and outer ring and two sealing rings. For protection against heavy water impacts and other dirt contamination, a cover snap is fitted on the front side.
Advantages of an overrunning alternator pulley
· Damping of belt vibrations
· Reduced load on the belt drive
· Reduced tensioner movement
· Increased belt life
· Improved noise behaviour of the belt drive
· Increased alternator speed in the idling speed range
· Reduced belt slip and noise on the alternator drive wheel during gear
changes
· Increased fuel economy
Alternator
An alternator is an electromechanical device that converts mechanical energy to electrical energy in the form of alternating current.Most alternators use a rotating magnetic field but linear alternators are occasionally used...
, pulley
Pulley
A pulley, also called a sheave or a drum, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present...
and drive belt failure. To prevent this Overrunning Alternator Pulleys (OAPs) were developed that are designed to decouple the alternator from the rotational irregularities of the crankshaft in an internal combustion engine, as the alternator has the highest mass moment of inertia in the accessory belt drive. As a result of this decoupling the alternator is only driven using the acceleration components of the rotational irregularity of the crankshaft.
The overrunning alternator pulley consists of a pulley, an overrunning clutch unit with a double bearing support, a drawn inner ring and outer ring and two sealing rings. For protection against heavy water impacts and other dirt contamination, a cover snap is fitted on the front side.
Advantages of an overrunning alternator pulley
· Damping of belt vibrations
· Reduced load on the belt drive
· Reduced tensioner movement
· Increased belt life
· Improved noise behaviour of the belt drive
· Increased alternator speed in the idling speed range
· Reduced belt slip and noise on the alternator drive wheel during gear
Gear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....
changes
· Increased fuel economy