Operation Knob Backlash Prevention via Two-Color Molding
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Solution Overview
Problem
Existing vehicle operation devices often produce abnormal noise due to vibrations, which is a result of backlash between fitting parts, and there is a need for improved workability in their design.
Innovation Solution
The operation device features a cylindrical base member with through-holes and protruding parts that engage with a softer outer member and an inner member, using hook parts and hook fitting parts for secure alignment, and is manufactured through two-color molding to prevent backlash and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastic member is interposed between the dial base and the decorative member to prevent backlash, then abnormal noise is reduced, but the manufacturing complexity and workability deteriorate due to additional fitting steps
Solution Approach 1:
The patent removes the elastic member from the structure, extracting the problematic component that caused manufacturing complexity. Instead of using an elastic member interposed between the dial base and decorative member, the invention uses a rigid connection structure with positioning protrusions and grooves to achieve both backlash prevention and improved workability.
Solution Approach 2:
The patent merges the positioning and connection functions into a single rigid structure. The positioning protrusions and grooves are integrated directly into the dial base and decorative member, eliminating the need for separate elastic members and reducing the number of assembly steps.
2Adaptability or versatility
If multiple separate components are used in the operation knob, then the structure is more flexible, but the number of fitting steps increases and workability deteriorates
Solution Approach 1:
The patent combines multiple functions into fewer components. The dial base integrates the positioning protrusions, the decorative member includes the positioning grooves, and these work together as a unified structure that maintains structural flexibility while reducing assembly complexity.
Solution Approach 2:
The operation knob is segmented into essential functional components (dial base, decorative member, operation element) connected through simple positioning features. This segmentation maintains the necessary structural flexibility while minimizing the number of parts and fitting steps required.
Data Source
AI summary
There is provided an operation device. An operation knob rotatable on an axial line, configured to include: a cylindrical base member extending in an axial direction; a cylindrical outer member disposed on an outer side in a radial direction of the base member; and an inner member disposed on an inner side in the radial direction of the base member. The cylindrical outer member has protruding parts extending inward in the radial direction and abutting on the inner member via through-holes formed through the base member in the radial direction.