Dial Selector Unit with Offset Angle for Error Suppression
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Solution Overview
Problem
Existing dial selector units in vehicles face challenges in balancing operability and suppression of erroneous operations, where a protruding portion that reduces erroneous operations can lead to poor operability due to excessive inward protrusion and limited dial member height.
Innovation Solution
A dial selector unit design with a protruding portion and a dial member positioned radially outward, featuring an offset angle that increases at the rearward side when the dial member is at the initial position and decreases at the forward side when depressed, along with an inclined rearward upper face and a flat forward upper face, to prevent unintentional contact while maintaining operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protruding portion height is increased to suppress erroneous operations, then erroneous operation suppression is improved, but the dial member height is limited and operability becomes poor
Solution Approach 1:
The dial member is designed with different heights at different circumferential positions. Specifically, the height is smaller at the portion corresponding to the user's hand placement area (where erroneous operations occur) and larger at other portions (where intentional operations are performed). This local variation in height allows the protruding portion to effectively suppress erroneous operations while maintaining adequate operability for intentional dial operations.
2Reliability
If the protruding portion excessively protrudes inward into the vehicle cabin, then erroneous operation suppression is improved, but the dial member height is limited and operability becomes poor
Solution Approach 1:
Instead of uniformly increasing the protruding portion height, the invention applies local quality by varying the dial member height at different positions. The dial member height is reduced only at the specific portion where the user's hand naturally rests, while maintaining sufficient height at other portions for proper operational leverage and feel.
3Reliability
If the dial member height is reduced to prevent palm contact, then erroneous operation suppression is improved, but operability of the dial member becomes poor
Solution Approach 1:
The dial member is designed with position-dependent height characteristics. At the portion corresponding to the user's palm placement area, the height is reduced to prevent unintentional contact. At other portions where intentional operations are performed, the height is maintained at an adequate level to ensure proper operability, leverage, and tactile feedback.
Solution Approach 2:
The dial member exhibits asymmetric height distribution around its circumference. The height varies depending on the angular position, being smaller at the user-side portion and larger at opposite portions. This asymmetric design allows differentiated functionality: error prevention where needed and operational effectiveness where required.
Data Source
AI summary
A selector unit includes a protruding portion and a dial member. The dial member is configured to be displaced between an initial position and a depressed position along an axial direction of the protruding portion, and to be rotationally operable in a circumferential direction when depressed to the depressed position. An offset angle at a rearward side when the dial member is at the initial position is greater than the offset angle at a forward side when the dial member is at the depressed position. The offset angle means an angle between an extended line obtained by extending an upper face of the protruding portion outwards in a radial direction and a tangential line in contact with both the upper face of the protruding portion and an upper face of the dial member, in a section including a rotation axis of the dial member.