Dual Stepper Motor Headlamp Linkage for Vibration Resistance

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Solution Overview

Problem

Motor vehicle headlights using linear stepping motors for light module adjustment face issues with inconsistent light distributions due to deviations in motor positions, increased load inertia, and lack of vibration resistance, along with the challenge of finding a single motor that meets performance and cost requirements without risking self-blocking.

Innovation Solution

A motor vehicle headlight design utilizing two linear stepping motors connected through a coupling rod and a summation control rod, which allows for synchronized movement of light modules, compensates for deviations in motor movements and maintains vibration resistance without the risk of self-blocking, using a seesaw mechanism and adjustable bearings to manage length changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a single large linear stepper motor is used to adjust multiple light modules, then the actuating force and vibration resistance are improved, but the cost and availability of the motor deteriorate

Engineering Contradiction:
Improveactuating forceVSAvoidcost and availability
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The system divides the adjustment function into multiple smaller linear stepper motors (first linear stepper motor, second linear stepper motor) that work together through a connecting rod mechanism, rather than using one large motor. This segmentation allows the use of available standard motors while achieving the required total actuating force through mechanical advantage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines the output of multiple linear stepper motors through a connecting rod and summing control rod mechanism to achieve the equivalent actuating force of a single large motor. The forces from multiple motors are merged mechanically to adjust the light modules collectively.

Inventive Principle:
Principle #5Merging (Combining)

2Force

If multiple linear stepper motors are rigidly coupled to increase actuating force, then the force output is improved, but the risk of self-locking due to synchronization issues increases

Engineering Contradiction:
Improveactuating forceVSAvoidsynchronization stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The connecting rod acts as an intermediary element that couples the multiple linear stepper motors in a non-rigid manner. It allows the motors to work together to generate high actuating forces while preventing self-locking by accommodating slight position deviations through its pivot bearing, eliminating the need for perfect synchronization.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If the number of light modules is increased, then the illumination coverage is improved, but the load inertia and vibration resistance requirements increase

Engineering Contradiction:
Improvenumber of light modulesVSAvoidload inertia
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

The system segments the adjustment mechanism into multiple independent linear stepper motors, each capable of handling a portion of the total load. This allows the system to scale to multiple light modules without requiring a single motor with excessively high inertia resistance, as each motor only needs to handle a fraction of the total load.

Inventive Principle:
Principle #1Segmentation

4Reliability

If a large safety margin is maintained between adjustment forces and maximum permissible force, then the reliability is improved, but the actuating force capability deteriorates

Engineering Contradiction:
Improvesafety marginVSAvoidactuating force capability
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

By combining multiple linear stepper motors through the connecting rod mechanism, the system achieves the required total actuating force capability while each individual motor can operate within its safe force limits. The forces from multiple motors are merged to provide the necessary total force without requiring any single motor to exceed its maximum permissible force.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design achieves higher actuating forces and improved vibration resistance while preventing self-blocking, ensuring consistent light distributions and maintaining safety margins, all at competitive costs.

Implementation Method 1

first linear stepper motor (22), a second linear stepper motor (32)

Methodology Applied
Scientific EffectStepper motor: Linear Motor

Implementation Method 2

The first light module-side end of the first control rod is rotatably connected to the first end of the connecting rod about an axis perpendicular to the axis of rotation of the light module

Methodology Applied
Scientific EffectRotational joint: Hinge

Data Source

PatentEP3785991B1Motor vehicle headlamp whose light beam orientation can be adjusted by means of electric motors
Publication Date: 2022.03.23 MARELLI GERMANY GMBH
  • EP3785991B1 patent drawingFigure 1
  • EP3785991B1 patent drawingFigure 2
  • EP3785991B1 patent drawingFigure 3

AI summary

A motor vehicle headlight (10) is presented, comprising at least one light module (18, 30) which is pivotably mounted in the motor vehicle headlight, and comprising at least one linear stepper motor (22), a second linear stepper motor (32), a connecting rod (34) and a summing control rod (36), wherein the first linear stepper motor (22) has a first control rod (24), wherein the second linear stepper motor (32) has a second control rod (38), and wherein the connecting rod (34) connects the two control rods in the manner of a rocker, and the summing control rod (36) is articulated to the pivot point (40) of the rocker and transmits the linear movement of the pivot point (40) to the at least one light module (18, 30), which reacts to this with a pivoting movement.