Santa Fe L4-2.4L (2001)
Seat Belt Tensioner: Description and Operation
FUNCTION OF PRETENSIONER
When a vehicle crashes with a certain degree of impact from the front, the gas generator is ignited by the electrical firing signal from the SRSCM
(Supplemental Restraint System Control Module).
Gas from the gas generator causes movement of the piston in the manifold case (cylinder), which operates the rack gear.
The rack gear rotates a piston gear and a pinion rotates the planet gears.
Finally the webbing is retracted by the rotation of the spool. Therefore the pretensioner seat belt helps to reduce the severity of injury to the front seat
occupant by retracting the seat belt webbing to prevent the occupant from thrusting forward and hitting the steering wheel or instrument panel when the
vehicle crashes.