Anatomy of a windshield wiper: what are the wiper parts called?

With the onset of autumn slush or winter snowstorm, every driver is faced with a situation where visibility through the windshield becomes critical. At these moments, we often think about windshield wipers, which are colloquially referred to as “windshield wipers”. However, when the time comes for replacement or repair, it turns out that the system is more complicated than it seems at first glance. A lack of understanding of the names of individual components leads to the purchase of the wrong spare parts and unnecessary waste of time.

The design of the windshield wiper consists of many elements, each of which performs its own function. From the electric motor hidden deep in the engine compartment to the rubber lip that directly touches the glass, everything must work as a single mechanism. Knowing the correct terminology will allow you to accurately explain the problem to a salesperson at an auto parts store or a service technician, avoiding misunderstandings.

In this article we will examine in detail the anatomy of a glass cleaning system. We will go through all the components: from the electrical part to the mechanical levers. You will find out what is different gear housing from the leash, and why trapezoid is the heart of all mechanics. This knowledge will help you independently diagnose faults and correctly select the necessary components for your car.

Electric motor and gearbox: the heart of the system

The basis of the entire glass cleaning system is the electric motor. It is this component that converts the electrical energy of the battery into mechanical rotation. Modern electric motors Windshield wipers are usually made using a permanent magnet design and have a built-in parking system. This means that even if you turn off the wipers mid-stroke, they will automatically return to the down position before stopping.

The motor itself develops a high rotation speed, but low torque. In order to move heavy levers with brushes, especially those covered with ice or snow, a mechanism is needed to reduce speed and increase force. This function is performed gearbox, which is structurally combined with the engine into a single unit. Inside the gearbox there is a worm gear, which provides the required gear ratio.

There is also a limit switch inside the gearbox housing. It is responsible for stopping the engine in the park position. If your wipers stop retracting under the hood when turned off, the problem often lies in the contact group of this unit. Three-brush The engine allows you to implement two operating speed modes by switching the armature windings.

It is important to understand that replacing the motor is often required together with the gearbox, since manufacturers rarely supply the internal gears separately. Wear of plastic gears leads to a characteristic hum or complete jamming of the system. When purchasing a new unit, pay attention to the number of splines on the output shaft, since their number may differ for different modifications.

Why is the wiper motor humming?

Most often, the hum occurs due to drying out of the lubricant in the gearbox or wear of the plastic gears. In winter, the cause may be a frozen brush, which creates excess load on the motor shaft.

Lever and rod system: movement mechanics

The transmission of rotation from the gearbox to the brushes is carried out through a complex system of levers and rods, which together are often called a trapezoid. crank, mounted on the output shaft of the gearbox, converts rotational motion into reciprocating motion. It is he who sets the amplitude of the entire system.

From the crank the force is transmitted to the rod system. Rods are metal rods connected to each other by hinges. These joints are often called "pins" or bushings. High-quality systems use plain bearings or even ball bearings, while budget systems use bushings made of non-ferrous metals or special plastic. Over time, play appears at the joints, which leads to knocking and uneven operation.

The design of the trapezoid can be different. Some cars use a single frame structure, where all the rods are rigidly connected. Other models use a system with separate levers for each brush, connected by a central rod. Windshield wiper trapezoid - this is a critically important unit, since its misalignment or deformation will lead to the fact that the brushes will touch each other or go beyond the working stroke.

Particular attention should be paid to the material used to make the rods. Steel elements are susceptible to corrosion, which can lead to jamming of the hinges. Aluminum alloys are lighter, but more prone to deformation under mechanical stress, for example, when trying to tear off a frozen brush with your hands.

Wiper arms: external interface

The arm (or windshield wiper arm) is the visible part of the mechanism that protrudes above the car body. This is what we grab with our hands when we need to lift the brush to replace or clear snow. Structurally, the leash consists of a base, which is put on the splines of the trapezoid shaft, and an arm, at the end of which a brush is attached.

The key element of the leash is spring. It provides the necessary pressing force of the brush to the glass. If the spring is weakened, the brush will not clean the glass well at high speeds, leaving uncleaned sectors. If the force is too great, this will lead to accelerated wear of the rubber and the appearance of squeaks. Some modern models use aerodynamic leashes that are pressed by the oncoming air flow.

The driver is attached to the shaft through a nut or a special locking mechanism. A situation often occurs when the splines on the shaft or inside the mounting hole of the driver “lick off”. In this case, the leash begins to rotate, and the wipers stop returning to the parking zone or work in violation of the geometry. To remove a soured leash, it is recommended to use a special puller so as not to damage the trapezoid shaft.

There are many types of attachments for brushes to leashes. The most common are Hook, Bayonet, Pin Lock and Side Pin. When purchasing new leashes or adapters, you need to know exactly the type of attachment, since there are no universal solutions. Adapters allow the use of modern frameless brushes on old leashes, but they add extra weight and windage.

Brushes and rubber elements: cleaning quality

The windshield wiper blade directly cleans the glass. It consists of a frame (metal or plastic) and a working element - a rubber band. In frame brushes, a rocker arm system distributes pressure evenly along the entire length of the rubber band, adapting to the curvature of the windshield. However, in winter, snow and ice accumulate in the hinges of the frame, which blocks the operation of the mechanism.

Frameless brushes do not have this drawback. They use an elastic metal plate embedded in a rubber profile. This design ensures an even fit over the entire area and better cleans the glass at high speeds. Hybrid brushes combine the advantages of both types: they have a closed casing that protects the mechanism from icing, and a frame structure for pressure distribution.

The most important element is working edge rubber. It is she who removes the water film. The quality of the rubber determines the service life and the absence of streaks. Cheap rubber quickly hardens in the cold and begins to leave streaks. Graphite coating on the edge improves sliding and reduces noise during operation.

It is recommended to change not only the rubber band, but also the entire brush, since the metal frame gets tired over time and loses its pressing force. However, to save money, you can only change elastic band (insert). In this case, it is important to select the profile exactly according to the shape of the original, otherwise the new insert will not fit into the grooves or will be skewed.

Comparative table of system elements

To make it easier to understand the differences between the main components, we have compiled a summary table. It will help you quickly navigate the terms when ordering spare parts or discussing repairs with a mechanic.

Part name	Main function	Typical faults	Material of execution
Electric motor	Creation of torque	Winding combustion, wear of motor brushes	Metal, copper, plastic
Trapezoid	Motion transmission and transformation	Play in hinges, corrosion of rods	Steel, aluminum
Leash	Pressing and moving the brush	Weakening of the spring, licking of the splines	Steel, plastic
Brush (frame)	Fixing the working edge	Corrosion of rocker arms, loss of elasticity	Metal, plastic
Rubber band	Direct glass cleaning	Edge wear, rubber petrification	Special rubber, graphite

The table shows that the system consists of dissimilar materials. Metal parts are subject to rust, and rubber parts are subject to aging and temperature influences. Understanding this helps predict the life of parts. For example, in severe winter conditions, the rubber elements and plastic bushings of the trapezoid will be the first to fail.

Washing system: auxiliary elements

Although the washer system is not formally part of the wiper mechanism, it is inextricably linked with their operation. Without liquid injectors will not be able to wash away the dirt, and dry brushes will only smear it across the glass, damaging the rubber edge. The main elements here are the tank, pump and injectors.

The washer pump (pump) creates the pressure necessary to supply the fluid. It is a small electric motor with an impeller. A common problem is clogging of the filter mesh on the pump intake pipe or the nozzles themselves. In winter, frozen liquid can rupture the pump housing or pipes.

Nozzles come in fan and jet types. Fan nozzles They spray the liquid in a wide veil, which allows you to save washer fluid and clean the glass better. Jets hit precisely. Often the nozzles are built into the wiper arms or in the hood. The jet direction is adjusted using a thin needle or a special key.

⚠️ Attention: Never turn on the washer pump if the reservoir is empty or the fluid is frozen. Dry operation leads to overheating and rapid failure of the pump electric motor.

The washer system pipes become dull and crack over time. If you notice that fluid is not reaching the injectors or is dripping under the car, first inspect the connections and hoses. The use of low-quality fluid containing aggressive solvents can accelerate the destruction of rubber pipes and plastic elements of the tank.

Diagnosis and typical problems

Understanding the names of wiper parts allows you to effectively diagnose problems based on symptoms. If the wipers work slowly, but with a characteristic hum, most likely the problem is in the mechanical part - it has soured trapezoid or the lubricant in the gearbox has dried out. If the motor hums, but the shaft does not rotate, the plastic gear in the gearbox may have been cut off or the bushing has turned.

The situation when the wipers stop in an arbitrary place indicates a malfunction of the parking limit switch or a violation of the leash adjustment. If the blades squeak on dry glass, this may be a sign of worn rubber, dirty edges, or an incorrect angle of the blade relative to the glass surface. Sometimes simply cleaning the rubber with alcohol or replacing the brushes helps.

Brush runout (“jumping”) is often caused by an incorrect angle of the driver or loss of elasticity of the brush frame. The reason may also be the poor quality of the glass itself (presence of micro-scratches) or the use of aggressive chemicals that made the rubber “oaky”. In some cases, lubrication of the axis of rotation of the leash is required, since souring there creates resistance that the spring cannot overcome.

⚠️ Attention: If jerking or jamming occurs, do not try to forcefully turn the levers with your hands while the engine is running. This can lead to breakage of gear teeth or burnt out motor windings.

Regular prevention prolongs the life of the entire system. It is enough to lubricate the trapezoid hinges a couple of times a year (if the design allows) and monitor the condition of the rubber bands. It is also important to clean the drive axles from dirt and rust so that they rotate freely in their seats.

Frequently asked questions (FAQ)

How often should windshield wiper blades be replaced?

The recommended replacement interval is once a year or every 30-40 thousand kilometers. However, in harsh climatic conditions (temperature changes, reagents on the roads), the resource can be reduced to 6 months. The main criterion is the appearance of uncleaned stripes and deterioration in the transparency of the glass after the passage of the brush.

Is it possible to lubricate the windshield wiper trapezoid with regular lithium grease?

You can use thick lubricants like Litol-24, but with caution. In the cold they can thicken, which will slow down the work of the wipers. It is better to use specialized frost-resistant lubricants for plastic and metal joints that retain elasticity at low temperatures.

Why do new brushes leave streaks?

There may be several reasons: factory defective rubber, incorrect installation (inverted working edge), contamination of the glass with an oil film, or weakening of the driver spring. Always clean the glass thoroughly with a degreaser before replacing the blades.

What to do if the wipers do not return to their original position?

First of all, check that the driver is securely fastened to the shaft splines. If the fastening is normal, the problem is most likely in the limit switch inside the motor gearbox or in a maladjustment of the parking mechanism. Requires disassembly of the unit and diagnostics of the electrical part.

What is the difference between winter and summer brushes?

Winter brushes (usually frameless or with a closed frame) are made of frost-resistant rubber that does not harden at extremely low temperatures. Summer options may be cheaper, but in frosts below -15°C they become rigid and no longer adhere tightly to the glass, leaving uncleaned areas.