The device and principle of operation of car wipers

All modern cars are equipped with windscreen wipers or "wipers", which are designed to clean the windshield from dirt, dust or precipitation. With their help, the driver can significantly improve visibility without leaving the passenger compartment. Automotive windshield wipers are an integral part of the vehicle's structure, and their failure prohibits the operation of the vehicle.

Windshield wiper system

Regular windshield wipers are designed to remove dirt, dust, and excess precipitation from its surface. This allows you to increase the visibility of the road at any time, including bad weather conditions: heavy rain or snow. For greater efficiency, the device is combined with a windscreen washer that sprays a special high-pressure washer fluid onto the glass surface. Thus, the glass is cleared of adhering dirt and insects.

Some vehicles have a rear wiper and special headlight cleaning devices (washers). This ensures traffic safety in all weather conditions. The frequency and duration of the wiper operation is regulated by the driver from the passenger compartment.

Structural elements of wipers

Design features depend on the type of device and the type of fasteners. A standard wiper circuit consists of the following parts:

• lever drive (trapezoid);
• leashes;
• relay for operating modes control;
• electronic control unit (if any);
• an electric motor with a gear;
• hinged mountings;
• brushes.

Additionally, control devices are provided. For example, for manual control, a steering column switch for operating modes of the wipers is used, and for automatic mode, a special electronic control unit and a sensor for analyzing glass contamination (rain sensor) are installed in the vehicle.

Principle of operation of the device

Despite the simple functionality of the cleaning system, it is necessary to understand how the wipers work. The main nuances you need to know about:

1. The electromagnetic relay receives the control command and sets the operating mode of the brushes. Depending on the vehicle, the cleaners can operate in intermittent mode at short intervals of 3-5 seconds, constantly move at a set speed, and also switch to washing mode with the washer on.
2. The wiper motor is powered by the vehicle electrical system. The exact wiring diagram depends on the car model.
3. The wiper arms, and with them the brushes for cleaning the glass, are driven by an electric motor with a worm gear and a lever drive (trapezoid). The trapezoid transmits and converts the rotational movement from the electric motor to the brushes, which, firmly pressing against the working surface, remove dirt and moisture from the glass.

A properly configured system should not leave streaks or mechanical damage on the glass surface, as well as make noise during operation. In the event of such problems, it is necessary to quickly eliminate the malfunction.

How the trapezoid works

The wiper trapeze consists of a system of rods and levers that convert the rotary motion from the gearbox into the reciprocating motion of the wiper rods. The standard device should fulfill the following functions:

• the movement of the brushes when the wiper motor is running;
• ensuring the required amplitude and speed of cleaning;
• the wiper arms with two or more brushes must move synchronously.

The trapezoid, like the electric motor, is an important component of the system. In case of any malfunctions (the appearance of backlash) in its work, the efficiency and quality of glass cleaning deteriorates. For greater reliability, trapezium elements are made of sheet steel, which is resistant to aggressive environments, and also has a high bending stiffness.

Depending on the design of glass cleaners, trapeziums can be one-, two- and three-brush, and according to the principle of operation - symmetrical and asymmetric.

Wiper motor

The wiper motor has a basic design regardless of the vehicle model. The main elements include the electric motor itself and the gearbox (usually a worm gear), which increases the force from the electric motor several times. Modern devices can be equipped with additional elements, including fuses for protection against heavy loads, heating elements for operation at low temperatures, and much more.

The wiper motor is the most important element of the system, which ensures its efficiency. The brushes must fit snugly against the glass and move freely over it, otherwise there is an increased load on the electric motor.

Purifier management

The windshield wiper system can be controlled in two ways - electronic and electrical. The latter option implies manual change of operating modes. There is a special control lever under the steering wheel that allows you to turn on the device, adjust the pause in the operation of the wipers and change the cleaning modes. But this option requires the constant participation of the driver.

The electronic control system is completely autonomous and does not require human intervention. A special electronic unit and a rain sensor are installed in the car, which analyzes the cleanliness of the glass and weather conditions. Electronic control provides a wide range of functions:

• automatic switching on and off;
• changing the parameters of the cleaner;
• blocking the motor in the presence of obstacles on the windshield;
• additional cleaning with a windscreen washer;
• prevention of freezing of brushes when the engine is off.

Types of brushes

Car manufacturers provide car owners with a choice of brush types. Depending on the design and performance, they can be of the following types:

1. Frame brushes are the best and most affordable option. They adapt well to the working surface of the windshield, but deteriorate the quality of cleaning at subzero temperatures and high speeds.
2. Frameless windshield wipers are a more expensive option that provides high-quality glass cleaning. The device is more resistant to freezing, and also lasts longer in operation. Among the disadvantages, it is necessary to note the complexity of the selection of brushes to ensure proper adhesion to the glass.
3. Hybrid wipers are often referred to as winter wipers due to their closed design and moisture resistance. Ideal for areas with low temperatures where it is important to ensure the performance of the purification system.

Ways of attaching brushes

Until 1999, most car manufacturers used a hook or Hook type of wiper attachment. This is a universal device in the shape of the letter "U", which allows you to snap the brush and not worry about the reliability of its installation. Currently, the following types of mounts are gaining popularity:

1. Side Pin - Introduced in 2005 on BWM, Volvo and other vehicles. Allows you to fix the brushes with a special side pin 22 or 17 mm.
2. Button or "Push Button" - adapter for standard 16 mm wiper blades. It is enough to snap on the device for fastening, and to remove it, you need to press a special button.
3. Pin lock - fixing brushes with a special built-in lock. Used in Audi vehicles.

This is not a complete list of types of fasteners. Each manufacturer can use their own designs for fixing the brushes.

Despite the relative simplicity of windshield wipers, it is difficult to imagine a modern car without them. Drivers can control the operation of the wipers directly from the passenger compartment, remove dirt and improve the visibility of the road situation. And electronic systems automatically monitor the cleanliness of the glass, increasing the comfort and safety of driving without human intervention.