Decoupler Isolator with Toric Spring Shell and Wrap Spring Groove

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Solution Overview

Problem

Existing decouplers, while satisfactory for their intended use, are susceptible to improvements in design and functionality, particularly in the transmission of rotary power and vibration damping, as they often rely on spring grooves and toric surfaces without optimized configurations for enhanced performance.

Innovation Solution

A decoupler design featuring a drive member, hub, and isolator with a wrap spring, helical coil springs, and a carrier assembly that includes a carrier plate and spring shell with a toric inner surface, where the helical coil springs are disposed between the hub and the carrier assembly, and the wrap spring's proximal end is received in a spring groove, enhancing rotary power transmission and vibration damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wrap spring with spring groove is used to fix the spring, then the spring positioning is improved, but the complexity of the spring fixing mechanism increases

Engineering Contradiction:
Improvespring positioningVSAvoidspring fixing mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring groove is integrated directly into the wrap spring structure itself, combining the spring element and the positioning feature into a single component. This eliminates the need for separate fixing mechanisms while maintaining reliable spring positioning through the groove geometry.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If helical coil springs are received in a toric inner surface of the spring shell, then the vibration damping performance is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvevibration damping performanceVSAvoidtoric inner surface
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The spring shell is designed with a toric (doubly curved) inner surface that provides optimal contact and support for the helical coil springs. The curved geometry distributes loads more evenly across the spring contacts, improving vibration damping while the curvature itself helps accommodate manufacturing tolerances through its geometric properties.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the rim of the carrier plate abuts the axial end of the wrap spring, then the axial positioning is improved, but the contact stress increases

Engineering Contradiction:
Improveaxial positioningVSAvoidcontact stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The carrier plate rim is designed as a segmented or distributed contact structure rather than a single point contact. This segmentation distributes the axial positioning load across multiple contact points along the rim, reducing peak contact stress while maintaining effective axial positioning of the wrap spring.

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 decoupler effectively transmits rotary power and dampens vibrations, providing improved performance and reliability by utilizing a combination of helical coil springs and a toric spring shell configuration, which enhances the decoupling efficiency and reduces wear and friction.

Implementation Method 1

The helical coil springs are disposed between the hub and the carrier assembly

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

dampens vibrations, providing improved performance and reliability

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

The wrap spring includes a plurality of helical coils and a proximal end... transmit rotary power between the drive member and the hub

Methodology Applied
Scientific EffectTorsional elasticity: Elasticity

Data Source

PatentEP2753839B1decoupler
Publication Date: 2019.03.20 LITENS AUTOMOTIVE INC
  • EP2753839B1 patent drawingFigure 1
  • EP2753839B1 patent drawingFigure 2
  • EP2753839B1 patent drawingFigure 3~4

AI summary

A decoupler that includes a drive member, a hub and an isolator that is configured to transmit rotary power between the drive member and the hub in a predetermined rotational direction. The isolator includes a wrap spring, a plurality of helical coil springs, and a carrier assembly. The wrap spring includes a plurality of helical coils and a proximal end. The helical coil springs are disposed between the hub and the carrier assembly. The carrier assembly includes a carrier plate and a spring shell. The carrier plate has a plate member with a rim and a spring groove. The rim abuts an axial end of the wrap spring. The proximal end of the wrap spring is received in the spring groove. The spring shell is assembled to the carrier plate and has a toric inner surface into which the helical coil springs are received.