Head-Up Display Gear Creep Correction
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Solution Overview
Problem
Head-up display (HUD) devices in vehicles experience positional deviations of virtual images due to creep deformation of transmission gears caused by environmental temperature changes, leading to an undesirable sense of incongruity for occupants.
Innovation Solution
The HUD device incorporates a control unit that corrects the rotational position of the stepping motor by predicting and adjusting for creep deformation in specific gears, using a temperature sensor to detect when the environmental temperature reaches a predicted deformation temperature, thereby minimizing the positional deviation of the virtual image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a reduction gear mechanism with resilient member is used to eliminate backlash, then manufacturing precision of virtual image display position is improved, but reliability deteriorates due to creep deformation at high temperatures
Solution Approach 1:
The control unit performs preliminary correction of the stepping motor's rotational position based on the detected temperature. When the temperature reaches or exceeds the predetermined threshold, the control unit advances the rotational position by a predetermined amount before creep deformation occurs, thereby preventing display position deviation even when the resilient member deforms at high temperatures
Solution Approach 2:
The invention implements a feedback mechanism where the control unit continuously monitors the temperature of the reduction gear mechanism and automatically adjusts the stepping motor's rotational position in response to temperature changes. This closed-loop control compensates for the thermal effects on the resilient member, maintaining reliable display position stability across varying temperature conditions
2Manufacturing precision
If resilient member is used to generate restoring force for gear engagement, then manufacturing precision is improved by eliminating backlash, but device complexity increases
Solution Approach 1:
The resilient member automatically performs the function of eliminating backlash through its elastic restoring force without requiring external control or adjustment mechanisms. The member self-adjusts to maintain gear engagement precision, and the control unit simply compensates for thermal effects rather than directly controlling the mechanical precision
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 solution effectively inhibits the deviation of the virtual image display position caused by creep deformation, ensuring a stable and accurate display of vehicle-related information even at elevated temperatures, thereby enhancing user experience and reliability.
Implementation Method 1
a resilient member that generates a restoring force in a direction that the plurality of transmission gears are engaged with each other
Implementation Method 2
the environmental temperature of transmission gears rises in a vehicle. As a result, the transmission gears incur creep deformation in the manner of increasing a backlash at a place where the transmission gears link with each other by engagement
Implementation Method 3
An environmental temperature of the specific gear, at which the specific gear is predicted to incur the creep deformation, is defined as a predicted deformation temperature
Data Source
AI summary
A head-up display device includes an optical unit that includes a drivable reflecting mirror and adjusts a virtual image display position by driving the mirror, a reduction gear mechanism rotatably including transmission gears, a resilient member that generates restoring force in a direction to engage the gears, and a control unit controlling a rotational position of the stepping motor based on an adjustment command by a vehicle occupant. At least one gear predicted to incur a creep deformation is a specific gear. An environmental temperature of the specific gear where the deformation is predicted is a predicted deformation temperature. A deviation predicted to be caused at the display position by the deformation at the predicted deformation temperature is a predicted display deviation. The control unit corrects the rotational position in a direction to reduce the predicted display deviation when the environmental temperature rises to the predicted deformation temperature or higher.