Headlamp Aiming Biasing Member for Preload Stability
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Solution Overview
Problem
Tolerance stack-ups and clearance issues in vehicle lamp assemblies, such as headlamps, affect aiming stability and capability, leading to potential binding and shifts in aim due to factors like hood slam, road bumps, and thermal loads.
Innovation Solution
A biasing member is used to generate a preload force between the motor sled and the housing, stabilizing the headlamp components and maintaining necessary tolerances and clearance to prevent binding and maintain aim.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tolerance stack-ups and clearance issues are present in the headlamp assembly, then the assembly is easier to manufacture, but the aiming stability deteriorates due to binding and aim shifts
Solution Approach 1:
The biasing member applies a preliminary counteracting force to offset the effects of tolerance stack-ups and external disturbances before they can cause binding or aim shifts. By pre-loading the motor sled assembly in a specific direction, the system proactively prevents clearance issues from developing into binding conditions, thereby maintaining aiming stability despite manufacturing tolerances
Solution Approach 2:
The biasing member changes the force parameter within the headlamp assembly by introducing a controlled preload force. This parameter change compensates for the cumulative effect of tolerance stack-ups across multiple components, ensuring that the motor sled maintains proper clearance and does not bind during operation, thus resolving the contradiction between ease of manufacture and aiming stability
2Adaptability or versatility
If the motor sled is allowed to move freely to adjust aim, then the aim adjustment capability is improved, but the aiming stability deteriorates due to shifts caused by external forces
Solution Approach 1:
The biasing member acts as a mechanical counterweight that applies a stabilizing force opposite to external disturbances such as hood slam and road bumps. This counteracting force prevents the motor sled from shifting unintentionally while still allowing controlled movement for aim adjustment, thus maintaining both adaptability and stability
Solution Approach 2:
The system employs dynamic force balance where the biasing member provides a variable counteracting force that adapts to external conditions. The spring-based biasing member dynamically adjusts its opposing force based on the position and external loads, enabling the motor sled to maintain stable positioning during normal operation while remaining movable for adjustment purposes
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
The biasing member enhances headlamp aim stability and capability by reducing shifts in aim due to external forces, ensuring the headlamps remain within the defined tolerance range over time.
Implementation Method 1
the biasing member comprises a coil spring
Implementation Method 2
the biasing member generates a preload force to bias the motor sled away from the housing
Implementation Method 3
the biasing member comprises a flex arm
Data Source
AI summary
A method and system include a housing, a vehicle lamp assembly that is supported by the housing, and a motor sled that is supported for movement relative to the housing. An adjustment member is coupled to the motor sled, and the motor sled is moveable by the adjustment member to adjust an aim of the vehicle lamp assembly. A biasing member reacts between the motor sled and the housing to provide a pre-load.