Asymmetric Tolerance Ring Torque Slip Control

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Solution Overview

Problem

Current tolerance rings in steering assemblies lack the ability to effectively differentiate torque transmission between clockwise and counter-clockwise rotations, leading to inefficiencies in torque coupling and potential slippage issues.

Innovation Solution

A tolerance ring with a cylindrical body and radially protruding wave structures, featuring asymmetric cross-sections and extensions, is designed to create distinct torque break points for clockwise and counter-clockwise rotations, ensuring a ratio of torque required for each direction is greater than 1, enhancing torque coupling precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional tolerance ring with symmetric protrusions is used, then the interference fit is provided between components, but the torque coupling effect is insufficient and slippage occurs in both rotational directions

Engineering Contradiction:
Improvetorque coupling reliabilityVSAvoidtolerance ring structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by configuring the tolerance ring with asymmetric protrusions that have different engagement characteristics for clockwise and counter-clockwise rotations. The protrusions are designed with specific geometries that create different torque break points for each rotational direction, thereby providing differentiated torque coupling effects and preventing slippage more effectively than symmetric designs.

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If very close tolerances are required for press fits and splines to transmit torque, then torque transmission accuracy is improved, but manufacturing costs increase

Engineering Contradiction:
Improvetorque transmission precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the tolerance ring, specifically the shape, size, and distribution of the protrusions, to create asymmetric engagement characteristics. This allows the component to achieve precise torque transmission through its designed geometry rather than requiring extremely tight manufacturing tolerances on all surfaces, thereby reducing manufacturing costs while maintaining torque transmission accuracy.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a tolerance ring with asymmetric protrusions is designed to create distinct torque break points, then torque differentiation between rotational directions is improved, but the device complexity increases

Engineering Contradiction:
Improvetorque break point precisionVSAvoidtolerance ring design complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the tolerance ring into multiple protrusions with different geometries and positions. Each protrusion is designed to engage at specific torque levels and rotational directions, creating distinct torque break points. This segmentation allows precise control over torque transmission characteristics while distributing the complexity across multiple simple geometric features rather than one complex continuous structure.

Inventive Principle:
Principle #1Segmentation

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 tolerance ring achieves improved torque differentiation and coupling efficiency by creating distinct torque break points for each rotational direction, reducing slippage and enhancing assembly stability in steering assemblies.

Implementation Method 1

a plurality of wave structures protruding radially from the undeformed portion. Each wave structure is located between, and connected to, undeformed sections

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3014134B1Tolerance ring with divided torque slip
Publication Date: 2019.10.09 SAINT GOBAIN PERFORMANCE PLASTICS RENCOL LIMITED
  • EP3014134B1 patent drawingFigure 1A~1B
  • EP3014134B1 patent drawingFigure 2~3B
  • EP3014134B1 patent drawingFigure 4A

AI summary

A tolerance ring (100) is adapted to be deployed between inner and outer components. The tolerance ring includes a generally cylindrical body (102). The sidewall (104) can include an undeformed portion (122). The sidewall can further include a plurality of wave structures (130). The wave structures can protrude radially from the undeformed portion. Some or all wave structures can protrude inwardly or can protrude outwardly. Furthermore, the tolerance ring when placed in an assembly having an inner component and an outer component can have a first torque break-point T iin a first rotational direction. A torque break point for an assembly comprising an inner component, an outer component, and a tolerance ring is the torque at which slippage occurs.