The power window motor
is a small motor that has an attached worm gear. This worm gear is a length of metal with a spiral on one end, similar to that of a screw.
The worm is attached to a gear; this circular gear has teeth around the outside. We can all picture this as a form of cog. As the worm turns it moves the gear by linking the teeth inside the spiral; the gear is then linked to several spur gears. Spur gears are used to create gear reductions in machines with motors.
The worm is fixed at a specific angle to the gear, which allows the worm to turn the gear, but prevents the gear from turning the worm. The motion of the worm and gears create a gear reduction which gives enough force to turn or rotate things, this is called torque.
There are supporting bars below each electric window and attached to each bar is an arm. This arm slides along the bars as the window rises and falls. The other end of the arm has a plate with teeth that slot into the teeth of the gears; as the gears turn so does the arm and in turn raises or lowers the window glass. On the opposite side of the bars is a counter arm that counteracts the weight of the window, so if the main arm is raised on the right side of the window the counter arm will be raised on the left, ensuring that the glass rises and falls evenly and level.
The mechanisms are very similar in manual windows as that of power windows, but instead of the motor turning the gears the crank handle does the work.