What is the Principle of Windshield Wipers?
2 Answers
The power source of windshield wipers comes from an electric motor, which is the core of the entire wiper system. The quality requirements for the motor in windshield wipers are quite high, typically using a DC permanent magnet motor. The wiper motor installed on the front windshield is usually integrated with the worm gear mechanical part. The function of the worm gear mechanism is to reduce speed and increase torque. The output shaft drives a four-bar linkage mechanism, which converts continuous rotational motion into a left-right oscillating motion. Below is a brief introduction to the principle of windshield wipers: 1. The wiper motor adopts a 3-brush structure to facilitate speed change. The intermittent time is controlled by an intermittent relay, utilizing the motor's return switch contacts and the charge-discharge function of the relay's resistor-capacitor to make the wiper sweep at a certain cycle. The wiper blade rubber is the tool that directly removes rainwater and dirt from the glass. The blade rubber is pressed against the glass surface by a spring strip, and its lip must match the angle of the glass to achieve the required performance. 2. Generally, there is a wiper control knob on the car's combination switch handle, with three positions: low speed, high speed, and intermittent. The top of the handle is the washer button switch. Pressing the switch sprays washer fluid, which works with the wiper to clean the windshield. The washer system is a common device in cars, consisting of a water storage tank, water pump, water delivery pipe, and spray nozzles. The water storage tank is usually a 1.5 to 2-liter plastic container, and the water pump is a miniature electric centrifugal pump that delivers the washer fluid from the storage tank to the spray nozzles. Through the squeezing action of 2 to 4 spray nozzles, the washer fluid is divided into fine jets directed at the windshield, working with the wiper to clean the windshield.
I've repaired quite a few windshield wiper systems, and their principle is actually quite straightforward. When the driver presses the switch, the wiper motor receives power and starts rotating. This rotational force is converted into a back-and-forth swinging motion through a linkage or shaft mechanism, which drives the wiper blades to move left and right across the windshield, clearing away rain and dirt. The core mechanism involves transforming the motor's circular motion into the linear reciprocating movement of the wiper blades, somewhat similar to lever operation. Many vehicles have different speed settings, achieved by varying the voltage to adjust the motor's rotation speed. From a safety perspective, without properly functioning wipers, visibility is compromised, increasing the risk of accidents. I recommend regularly checking the rubber blades for signs of aging or cracking and replacing them promptly. The motor and connecting components should also be protected from rust and kept lubricated. Some newer cars feature automatic rain-sensing functionality, using optical sensors to detect rainfall and activate the wipers automatically, which is very convenient. Overall, understanding these mechanical details makes DIY maintenance much easier, reducing the need for frequent trips to the repair shop.
