What is the component of the rearview mirror switch on the exterior of the car?
There is no standard term "wiper assembly" in the exterior rearview mirror of a car. This expression is usually a misnomer or an industry non-standard term for the electric rearview mirror drive motor and its control circuitry. In professional context, its core function is to change the direction of the motor current to drive the mirror to rotate, and it actually corresponds to the "rearview mirror adjustment motor assembly" (including the motor, transmission gears, and control switch).
Core Definition and Essence
Essential Components: The rearview mirror adjustment motor (often a bidirectional DC motor), combined with a worm gear and worm wheel and other transmission mechanisms, converts electrical energy into mechanical motion to achieve the up and down, left and right angle adjustment of the mirror.
"Wiper" Principle: By changing the input motor's current direction through the control switch, the motor's rotation direction is changed, driving the mirror to deviate in different directions, rather than referring to the physical structure of the "commutator" in traditional DC motors.
Common Misconceptions: Some repair materials or old models refer to the manual-to-electric modification kit as an "electric commutator", which is actually the "motor drive module"; strictly speaking, "commutator" (Commutator) is the copper plate structure inside a DC motor and does not exist as an independent aftermarket component.
Main Components and Functions
Drive Motor: Each side of the rearview mirror usually has 2 motors (controlling the vertical and horizontal directions), which output torque after receiving control signals.
Transmission Mechanism: Includes worm gears, gears, or connecting rods, converting the motor's rotational motion into the minute angle displacement of the mirror, and having a self-locking function to prevent shaking during driving.
Control Switch: The driver's operation end, used to select the left/right rearview mirror and adjust the direction, by changing the circuit polarity to control the motor rotation.
Fault Manifestations and Replacement
Typical Faults: The mirror cannot be adjusted, abnormal noise during adjustment, motor jamming or only able to move in one direction.
Maintenance Method: Modern vehicles mostly adopt "modular design", when a fault occurs, they usually directly replace the "rearview mirror assembly" or "motor drive sub-assembly", rather than disassembling the tiny commutating structure inside.
If you see "rearview mirror commutator" in the parts catalog, it is recommended to check the specific part number. The actual corresponding item is mostly the "rearview mirror adjustment motor" or "electric adjustment actuator".
The exterior rearview mirror wiper assembly is the core execution component of the electric rearview mirror system. It is essentially a precision mechatronic device driven by a miniature DC motor, which converts electrical signals into mechanical motion and precisely controls the angle of the mirror. Core function
Angle adjustment drive: Receives instructions from the vehicle control module or switch, drives the gear set to cause the mirror to deflect in the horizontal (left and right) and vertical (up and down) directions, helping the driver eliminate blind spots and obtain the best rear-view view.
Position memory and reset: Cooperates with Hall sensors or potentiometers to provide position signals, achieving precise positioning of the rearview mirror angle; supports multi-driver perspective memory and automatically extends or folds when the vehicle is unlocked/locked.
Special scene linkage: When in reverse gear, the mirror can trigger the automatic downward flip function, allowing the driver to clearly observe the distance between the rear wheels and the curb, preventing scratches; some higher-end models support automatic steering follow-up, assisting in lane change view compensation.
Technical features
High-precision control: The modern brushless solution controls the error within ±0.5°, ensuring stable and non-shaking view.
High-reliability design: Must meet vehicle-grade requirements, including temperature resistance (-40°C to +85°C), waterproof and dustproof, and long lifespan (typically ≥100,000 cycles without failure).
In short, the reversing gear assembly solves the "how to move" problem, allowing the driver to safely and conveniently adjust the view range without getting out of the vehicle.
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