Composite Tolerance Ring with Elastomeric and PTFE Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional tolerance rings and bearings face challenges in achieving optimal frictional engagement and minimizing vibration and noise, as they often rely on strong material properties that result in high frictional forces, which can be unsuitable for applications requiring low sliding or rotational forces.
Innovation Solution
A composite tolerance ring design featuring a metallic annular band with an elastomeric layer and a low friction layer, such as PTFE, laminated to one side, which reduces friction and enhances sliding properties, allowing for improved torque control and noise reduction by decoupling mating parts without compromising other performance areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional tolerance rings use strong material properties (stainless or carbon steel) to provide maximal frictional engagement, then frictional forces increase, but sliding properties deteriorate and torque variation increases
Solution Approach 1:
The tolerance ring uses a composite structure combining a metallic annular band (spring steel) with an elastomeric layer and a low friction layer (PTFE). This composite material approach allows the ring to simultaneously achieve strong frictional engagement through the metallic band, flexible adaptation through the elastomeric layer, and low sliding friction through the PTFE layer, resolving the contradiction between maximal frictional engagement and good sliding properties
Solution Approach 2:
Different layers of the tolerance ring have different local properties: the metallic annular band provides structural strength and frictional engagement, the elastomeric layer provides flexibility and damping, and the low friction layer provides smooth sliding. This local differentiation of material properties allows each layer to optimize its specific function while working together as a unified component
2Force
If conventional tolerance rings use strong material properties to create strong contact, then frictional forces increase, but noise and vibration properties worsen
Solution Approach 1:
The composite structure with metallic band, elastomeric layer, and low friction layer creates a multi-functional component that maintains strong contact force through the metallic band while the elastomeric layer provides vibration damping and noise reduction, and the low friction layer reduces sliding-induced vibrations, thereby improving NVH properties
Solution Approach 2:
The elastomeric layer acts as a flexible element that dampens vibrations and reduces noise generated during operation. This flexible layer absorbs mechanical shocks and vibrations while maintaining the necessary contact pressure, thereby reducing harmful noise and vibration without compromising contact strength
3Stability of the object's composition
If conventional tolerance rings are designed for close fit to reduce relative vibration, then frictional forces increase, but sliding properties deteriorate
Solution Approach 1:
The composite structure allows the tolerance ring to maintain a close fit for stability while the low friction layer ensures smooth sliding. The metallic band provides structural integrity for close fitting, the elastomeric layer provides damping for vibration reduction, and the PTFE layer provides low friction for easy sliding, resolving the contradiction between close fit stability and sliding properties
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 composite structure provides advanced sliding and adjustment properties, enabling lower torque and noise levels while maintaining radial load strength, suitable for applications like steering columns and hinge assemblies, with consistent sliding force and reduced wear over the product's lifetime.
Implementation Method 1
an elastomeric layer secured to the metallic layer... a low friction layer may be laminated to at least one side of the annular band to improve sliding properties
Implementation Method 2
The annular band may be formed from spring steel... Tolerance rings are able to compensate for tolerances or misalignments
Implementation Method 3
The assembly may further comprise an adhesive or primer layer between the annular band and the elastomeric layer
Data Source
Figure 1A~1C
Figure 2~3C
AI summary
A bearing and tolerance ring (31) comprising an annular band (33) and an elastomeric layer (35) disposed on the annular band and a low friction layer (37) disposed on at least one of the annular band and the elastomeric layer, wherein the ring includes a plurality of waves with peaks and valleys that undulate and are adapted to contact a bore of an outer component and an outer surface of an inner component.