The Porsche windscreen wiper motor is comprised of two key parts, which are the worm gear and electric motor. These two technologies are mechanical in nature and when combined make the wipers work. This is achieved through a linkage which will convert the motor’s rotational output into the wiper’s motion.
The mechanical movement of the electric motors found in most windscreen wipers will be produced by DC, or direct current, and AC, or alternating current. These motors are usually comprised of six components, which are the field magnet, armature, brushes, axle, commutator, and DC based power supply. Once you understand how these motors work, you will understand the inner workings of windscreen wipers as well as electricity and electromagnetism.
Reduction Of The Gear And Motor
It takes substantial force for the wiper blades to accelerate to and fro along the windscreen. To generate the required force, the worm gear will be used on the electric motor’s output. The reduction of a worm gear will multiply the motor’s torque approximately fifty times, while simultaneously slowing the electric motor’s output by the same amount. Therefore, the gear reduction’s output produces a linkage which will move the wipers around.
Worm gears are favored in circumstances where significant gear reductions become necessary. It isn’t unusual for a worm gear to contain a 20:1 reduction; some even reach 300:1 or more. Many of these gears have a characteristic which is not found in other gear sets, which is the ability to turn a gear with ease, without the gear being able to move the worm. This is due to the fact that the worm’s angle is sufficiently shallow that when a gear attempts to move it, friction among the worm and gear will ensure the worm stays in place. This is not only important for windscreen wipers but other devices such as conveyor systems, where the locking feature will function like the brake whenever the motor isn’t spinning.
Within the motor or gear assembly is the electrical circuit, which will detect when wipers are in a down position. The circuit will maintain power for the wipers until which time they become parked near the windscreen’s bottom, at which point power flowing to a motor will be cut. The circuit will also position the wipers whenever they are in a setting which is intermittent.
Linkage involves the shortened cam which is connected to the gear reduction output shaft. The cam will spin around while a wiper motor is turning. The cam will be attached to an extended rod, and while the cam is spinning the rod will be moved to and fro. The extended rod is attached to a rod that is shorter and which will actuate the driver’s side wiper blade. Another extended rod will transfer the force from the side of the driver to the wiper blade on the passenger side.