HUD Barrel Cam Mechanism for Mirror Angle Adjustment
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Solution Overview
Problem
Conventional head-up display apparatuses face issues with precision in adjusting the tilting angle of the mirror due to point contact load concentration from vehicle vibrations, leading to abrasion and deformation, and limited resolving power from the use of lead screws and stepping motors.
Innovation Solution
A head-up display apparatus with a barrel cam having a spirally formed cam groove and a drive unit that includes a gear and motor, where the mirror link unit slides along the cam groove with elastic force application to ensure precise angle adjustment and distribute load through line contact, enhancing the resolving power and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lead screw and stepping motor are used to rotate the mirror, then the mirror can be adjusted to different angles, but the resolving power is limited due to difficulties in reducing the pitch of the lead screw or increasing the precision of the stepping motor
Solution Approach 1:
The patent replaces the traditional lead screw and stepping motor mechanical system with a cam mechanism. The cam profile is designed to directly convert rotational motion into precise angular adjustment of the mirror, eliminating the need for high-precision motors and lead screws while achieving superior resolving power through optimized cam geometry.
2Device complexity
If the link unit makes point contact with the driven power transmission unit, then the structure is simple, but load concentration from vehicle vibrations causes abrasion and deformation, reducing operational precision and optical performance
Solution Approach 1:
The patent transitions from point contact to line contact by designing the cam groove as a linear feature extending along the cam's axial direction. This dimensional change from zero-dimensional point contact to one-dimensional line contact distributes the load across the length of the groove, preventing stress concentration and reducing wear while maintaining structural simplicity.
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 solution allows for precise adjustment of the tilting angle of the mirror, improving the resolving power and optical performance by dispersing load through line contact and maintaining consistent rotating angles, thus preventing wear and deformation.
Implementation Method 1
an elastic member coupled to the mirror link unit and configured to apply elastic force to the mirror link unit so that the mirror link unit comes into close contact with the cam groove
Data Source
AI summary
A head-up display apparatus may include: a mirror; a housing installed on one side of the mirror; a drive unit installed in the housing; a barrel cam rotatably installed in the housing and coupled to the drive unit so that the barrel cam is rotated by the drive unit, with a cam groove formed in the barrel cam and inclined relative to an axial direction of the barrel cam; and a mirror link coupled to the mirror, and configured to move along the cam groove to rotate the mirror when the barrel cam rotates.