How Windshield Wipers Work
09-09-17, 02:12 PM
#1
Lexus Champion
Thread Starter
How Windshield Wipers Work
Here's how the windshield wipers work to clean the front window on your car.
This wiper and washer system in this video was demonstrated in a 2001 Toyota Corolla.
The windshield wipers move in a repetitive translation sweeping motion across the windshield. This motion comes from a motor, that rotates. Using a crank slider (push pull rod) in addition to a four bar linkage, the repetitive sweeping motion is achieved from the wiper motor. The motor is mounted to the body here:
The wiper motor assembly consists of a spiral gear that engages the drive gear. This prevents the wipers from being forced down by hand. This also provides torque multiplication and speed reduction.
On the back of the drive gear is 3 contacts with a break in it at the home position. When the break lines up, the position of the gear indicates The park position of the wipers, breaks the drive circuit, and thus the motor knows when to come to a stop.
The wiper switch contains all of the electronics for the intermittent function. The motor itself has a resistor for built in hi and low speed control.
A steel wiper blade consists of small linkages that attach the frame to the blade. This helps to distribute pressure across its surface and is called a whippletree mechanism.
Finally, the washer tank, consists of the level sensor and pump. The level sensor is a reed switch, simply a magnetic switch that turns on when the float drops below a certain level to turn on the warning light on the dash board. The pump is a tiny DC electric motor with a small impeller to provide fluid flow from the tank out to the nozzles.
Automatic rain sensing wipers use an infrared sensor on the inside of the top of the windshield to sense rain droplets through reflection. A computerized system then activates the windshield wipers accordingly to keep the windshield clear.
This wiper and washer system in this video was demonstrated in a 2001 Toyota Corolla.
The windshield wipers move in a repetitive translation sweeping motion across the windshield. This motion comes from a motor, that rotates. Using a crank slider (push pull rod) in addition to a four bar linkage, the repetitive sweeping motion is achieved from the wiper motor. The motor is mounted to the body here:
The wiper motor assembly consists of a spiral gear that engages the drive gear. This prevents the wipers from being forced down by hand. This also provides torque multiplication and speed reduction.
On the back of the drive gear is 3 contacts with a break in it at the home position. When the break lines up, the position of the gear indicates The park position of the wipers, breaks the drive circuit, and thus the motor knows when to come to a stop.
The wiper switch contains all of the electronics for the intermittent function. The motor itself has a resistor for built in hi and low speed control.
A steel wiper blade consists of small linkages that attach the frame to the blade. This helps to distribute pressure across its surface and is called a whippletree mechanism.
Finally, the washer tank, consists of the level sensor and pump. The level sensor is a reed switch, simply a magnetic switch that turns on when the float drops below a certain level to turn on the warning light on the dash board. The pump is a tiny DC electric motor with a small impeller to provide fluid flow from the tank out to the nozzles.
Automatic rain sensing wipers use an infrared sensor on the inside of the top of the windshield to sense rain droplets through reflection. A computerized system then activates the windshield wipers accordingly to keep the windshield clear.
09-09-17, 04:28 PM
#3
^^^ Agree, nice videos 
The toothbrush pointer 
The toothbrush pointer
09-12-17, 09:16 AM
#4
Lexus Champion
Thread Starter
I work as a mechanical engineer in the automotive aftermarket, but that's unrelated.
Thanks I'm glad you enjoy them.
09-12-17, 10:50 AM
#5
Lexus Fanatic
Nowadays with all the blades being beams, it's interesting how engineers didn't think of it say 15 years ago (the blade pictured has 8 pressure points--8, vs. a beam which has over 1,000)....once the angle of the arm changes, it seems a wiping system can no longer apply sufficient pressure, be it from adapters on the blade, or wobble from the linkage....p.s. replacing the linkage on my Nissan when it was over 16 y.o. was one of the most frustrating jobs due to access and rust...
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