In-Vehicle Display Locking Mechanism for Rattle-Free Manual Movement
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Solution Overview
Problem
In-vehicle display devices experience backlash and rattling due to gear misalignment and high manual load when moving the display member between positions, especially when the ignition is turned off, leading to noise and difficulty in manual operation.
Innovation Solution
An in-vehicle device with a movable member, a motor, detection switches, and a locking mechanism that uses backlash to self-lock the member when the ignition is off, allowing easy manual movement by reducing the load required to change positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a worm and worm wheel engagement structure is used in the drive mechanism, then the reduction ratio is high and the movable member can be self-locked, but the load when moving the movable member manually becomes excessively high
Solution Approach 1:
The patent applies dynamics by making the locking state changeable based on operational conditions. The locking mechanism is dynamically adjusted: it locks during normal operation to prevent rattling, but unlocks when manual operation is detected (through reverse rotation detection) to reduce the load required for manual movement. This resolves the contradiction by making the system adapt between locked and unlocked states rather than maintaining a fixed locking condition.
Solution Approach 2:
The patent changes the parameter of locking force based on operational mode. By detecting reverse rotation (which indicates manual operation attempt), the system changes the locking parameter from high (during automated operation) to low (during manual operation). This allows the same worm and worm wheel structure to provide both strong self-locking capability and easy manual operation by dynamically adjusting the engagement state.
2Object-generated harmful factors
If the movable member is self-locked when the main switch is OFF, then rattling and noise are prevented, but the movable member becomes difficult to move manually to the storage posture
Solution Approach 1:
The patent converts the harmful effect of the locked state (difficulty in manual movement) into a beneficial detection mechanism. When a user attempts manual movement, the reverse rotation of the movable member is detected as a signal to unlock the locking mechanism. Thus, the very resistance that seemed harmful becomes the trigger for releasing the lock, enabling easy manual operation while maintaining noise prevention during normal operation.
Solution Approach 2:
The patent implements feedback by using the movement detection switch to sense reverse rotation of the movable member. This feedback signal triggers the controller to change the locking state from locked to unlocked. The system continuously monitors the position and movement direction, and automatically adjusts the locking force based on the detected operation mode, resolving the contradiction between noise prevention and ease of manual operation.
3Measurement precision
If the drive motor is used to move the movable member, then precise positioning is achieved, but the motor and transmission cluster gear act as a load when manual operation is attempted
Solution Approach 1:
The patent applies dynamics by making the transmission system's engagement state changeable. During automated operation, the worm and worm wheel are engaged for precise positioning. During manual operation (detected by reverse rotation), the system dynamically disengages or reduces the locking force, allowing the movable member to move freely without the full load of the transmission mechanism. This resolves the contradiction by making the transmission system adaptive rather than static.
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
Prevents rattling and noise by self-locking the movable member when the ignition is off, allowing for easy manual operation with reduced load and efficient motor-driven movement when needed.
Implementation Method 1
at least one detection switch that detects movement of the movable member
Implementation Method 2
the movable member is stopped to eliminate occurrence of backlash in a gear in a power transmission path in a drive mechanism, and the movable member is self-locked
Implementation Method 3
a motor that moves the movable member
Data Source
AI summary
An in-vehicle device includes: a movable member; a motor that moves the movable member; at least one detection switch that detects movement of the movable member; and a controller that controls the motor based on a detected output of the detection switch. The in-vehicle device further includes: a locking mechanism unit that, upon determination by the controller based on the detected output from the detection switch that the movable member reaches an end point region in a movement direction, locks the movable member, and upon determination by the controller that a main switch is set to OFF, releases the lock; and a motor driver that, after the release of the lock by the locking mechanism unit, upon determination by the controller based on the detected output from the detection switch that the movable member is moved again, drives the motor to move the movable member.