Actuator Thermal Stability Using High-Temperature Plastic Limit Stops
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Solution Overview
Problem
Current actuators for headlamp leveling in vehicles face challenges with thermal stability, leading to inaccuracies and potential dazzling due to material expansion from thermoplastic materials used, which are not resistant enough to extreme temperature fluctuations.
Innovation Solution
The use of high-temperature plastic materials for limit stop elements and components in the actuator, such as a housing cover and ball head, minimizes thermal expansion and ensures stable positioning even under high temperature loads, employing a stepper motor for precise linear movement and bayonet interface for secure coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic material (e.g., PBT) is used for actuator components, then ease of manufacture is improved, but thermal stability deteriorates due to large coefficient of thermal expansion causing material expansion at extreme temperatures
Solution Approach 1:
The patent changes the material parameter by selecting a thermoplastic material with a low coefficient of thermal expansion (≤ 50×10⁻⁶/K) to reduce thermal expansion at extreme temperatures while maintaining ease of manufacture through injection molding processes
Solution Approach 2:
The patent employs composite construction by combining thermoplastic material for the limit stop element with metallic materials (steel or aluminum) for the gear component and actuator housing, creating a composite actuator system that leverages the dimensional stability of plastics and the mechanical strength of metals
2Manufacturing precision
If thermoplastic material is used for actuator components, then manufacturing precision is improved through molding processes, but measurement precision deteriorates due to loss of reference planes from material expansion
Solution Approach 1:
The patent selects thermoplastic materials with specifically controlled parameters (low coefficient of thermal expansion ≤ 50×10⁻⁶/K and melting temperature ≥ 325°C) to maintain reference plane stability and positioning accuracy across extreme temperature ranges from -40°C to +120°C
Solution Approach 2:
The patent incorporates a reference plane directly into the molded limit stop element during manufacturing, establishing a stable reference feature before the actuator is installed and operated, ensuring consistent positioning accuracy without requiring subsequent adjustment
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 provides high accuracy and thermal stability, maintaining precise positioning of headlamps across a wide temperature range, preventing dazzling and ensuring reliable operation.
Implementation Method 1
Temperature changes ranging from −40° C. to more than +120° C. are possible in automotive headlamps. These temperature changes and high thermal resistance requirements lead to variations in the material expansion of the components of a system
Data Source
AI summary
The invention relates to an actuator (1), having a motor (2) and an actuator component (3) operable by the motor (2), having a movable gear component (4) with a limit stop component (5a, 5b), and at least one limit stop element (6) with a reference plane serving as stop for the limit stop component (5a, 5b) of the gear component (4), wherein at least one limit stop element (6) and/or the first and/or the second limit stop component (5a, 5b) is/are made from a high-temperature plastic material. Furthermore, the invention of such an actuator (1) relates to the use of such an actuator for the headlamp leveling of a headlamp.