Worm Shaft Damper With Integrated Rubber Stop for Rattle Control
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Solution Overview
Problem
Conventional dampers for column type electric power steering (C-EPS) suffer from variations in stopping performance due to tolerance differences in peripheral parts, leading to rattle noise issues.
Innovation Solution
A damper design featuring a rubber unit with concave and convex parts, where the concave parts are grooved and shaped like whirlwind threads, providing a built-in stopping function to prevent excessive compression and reduce variations in stopping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional damper with peripheral stopping parts is used, then the stopping function is provided, but variation in stopping performance occurs due to tolerance differences in peripheral parts
Solution Approach 1:
The stopping function previously provided by separate peripheral parts is merged into the rubber unit itself through the groove structure. The groove formed in the rubber unit creates convex and concave surfaces that provide the stopping function inherently, eliminating the need for additional peripheral stopping components and reducing variation due to assembly tolerances.
Solution Approach 2:
The rubber unit serves dual purposes: it provides damping through its material properties and simultaneously provides the stopping function through its groove structure. This self-service approach integrates multiple functions into a single component, improving reliability without adding complexity.
2Object-affected harmful factors
If the rubber unit is compressed to prevent rattle noise, then the stopping function is required, but excessive compression occurs without proper stopping mechanism
Solution Approach 1:
The groove is formed at a specific location on the rubber unit to create localized convex and concave surfaces. This local structural modification provides the stopping function precisely where needed during compression, controlling the compression behavior to prevent excessive deformation while addressing the rattle noise issue.
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
The damper's integrated stopping function stabilizes compression, reducing the need for additional peripheral components and minimizing rattle noise by ensuring consistent performance.
Implementation Method 1
When a load is applied to the damper 50 by an external factor which causes rattle noise, the damper 50 undergoes approximately linear compressive deformation
Implementation Method 2
a rubber unit 52 made of a rubber material
Data Source
AI summary
A damper for electric power steering disposed on each of opposite ends of a worm shaft includes a rubber unit made of a rubber material, and a damper frame disposed on each of opposite sides of the rubber unit. The rubber unit includes a concave part which is concavely formed by forming a groove on an outer circumference thereof, and a convex part which is a convex remaining part.