Shift Device Knob Positional Restrictions for Mode Switching
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Solution Overview
Problem
Existing shift devices, such as those combining a rotatable knob with a push button, often lead to erroneous operations due to the lack of clear differentiation between modes, affecting vehicle driving safety.
Innovation Solution
A shift device with a rotatable and pushable knob that includes an alternating action generation unit, base position return unit, push restriction unit, and rotation restriction unit to prevent incorrect operations by restricting rotation and pushing when the knob is in specific positions, ensuring accurate mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shift device combines a rotatable knob with a push button for easy operation, then the ease of operation is improved, but erroneous operation increases due to lack of clear mode differentiation
Solution Approach 1:
The knob dynamically changes its degree of freedom based on its axial position. When pushed to the hold position, the knob transitions from allowing rotation to restricting rotation, and vice versa when pushed to the base position. This dynamic restriction of movement based on position clearly differentiates between selectable modes (rotational freedom) and confirmable modes (axial pushing), preventing erroneous operations while maintaining ease of use
Solution Approach 2:
Different operational characteristics are applied to different positions of the knob. At the base position, the knob allows rotation for mode selection. At the hold position, the knob restricts rotation but allows pushing for confirmation. This local differentiation of operational properties at different positions eliminates ambiguity and prevents incorrect operations
2Ease of operation
If the knob allows both rotation and pushing without restrictions, then the ease of operation is improved, but the device complexity increases due to need for multiple restriction mechanisms
Solution Approach 1:
The alternating action generation unit combines multiple functions into a single mechanism. It simultaneously generates the hold position when the knob is pushed, restricts rotation at the hold position, and enables the base position return function. By merging these functions into one integrated unit rather than separate mechanisms, the device achieves clear mode differentiation without excessive mechanical complexity
3Ease of operation
If the knob is pushed without position differentiation, then the ease of operation is improved, but the reliability decreases due to inability to distinguish between base position and hold position
Solution Approach 1:
The system provides tactile feedback through the alternating action generation unit that clearly distinguishes between the base position and hold position. When the knob is pushed, the driver feels the alternating action that confirms the position change. This feedback mechanism ensures accurate position recognition, preventing erroneous operations while allowing quick operation without visual confirmation
Data Source
AI summary
A shift device includes a knob that is rotatable about an axis and movable when pushed in the axial direction. An alternating action generation unit switches the knob, whenever the knob is pushed, between a base position and a hold position, which is separated from the base position in the axial direction. A base position return unit returns the knob to the base position when the knob has been rotated from the base position. A push restriction unit restricts pushing of the knob that has been rotated from the base position. A rotation restriction unit restricts rotation of the knob that is located at the hold position.