Freewheel Wave-Like Radial Spring for Compact Axial Support

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Solution Overview

Problem

Existing freewheel designs with reduced helical springs face challenges in securing the clamping element and spring support due to the reduced clamping gap, leading to unreliable functioning and increased manufacturing and assembly efforts.

Innovation Solution

A freewheel design featuring an elongated spring body with a wave-like course in the radial plane, which fills the clamping gap effectively and provides secure support for the clamping element, reducing the need for complex measures and lowering production and assembly costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the clamping gap is reduced in the axial direction to achieve a compact axial length, then the axial overall length is reduced, but the secure support of the clamping element on the helical spring and the secure support of the helical spring on the inner ring or outer ring cannot be guaranteed

Engineering Contradiction:
Improveaxial overall lengthVSAvoidsecure support of clamping element and spring
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The spring element is designed with an elongated spring body that extends in the radial direction rather than the axial direction. This dimensional change allows the spring to achieve sufficient length for reliable support functions while maintaining a compact axial overall length of the freewheel assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spring element uses a wave-like course configuration in the radial plane, changing the geometric parameters of the spring body. This wave-like structure increases the effective length of the spring in the radial direction, enabling secure support of the clamping element and reliable mounting on the rings without increasing axial dimensions.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the winding diameter of the helical springs is reduced to accommodate the reduced clamping gap, then the spring can fit in the narrowed space, but reliable functioning of the spring element cannot be ensured without complex measures for secure mutual connection and guidance

Engineering Contradiction:
Improvespring element sizeVSAvoidconnection and guidance measures
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The spring element transitions from a conventional helical spring with winding in the axial direction to a spring body with a wave-like course in the radial plane. This dimensional reorientation eliminates the need for complex connection and guidance measures by naturally aligning the spring's elongation direction with the radial clamping gap, simplifying the overall device structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The wave-like spring body configuration enables the spring to self-align and self-support within the clamping gap. The elongated radial structure provides inherent stability and guidance, eliminating the need for additional complex connection and guidance components that would otherwise be required.

Inventive Principle:
Principle #25Self-service

3Reliability

If the clamping gap is increased in the radial direction to accommodate the spring element, then the spring can provide adequate support, but the clamping gap dimensions are constrained by the reduced axial design

Engineering Contradiction:
Improvespring support functionVSAvoidclamping gap dimensions
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The solution redirects the spring element's primary extension from the axial direction to the radial direction. This allows the clamping gap to be optimized with small axial dimensions for compactness while providing sufficient radial dimension for the spring element to extend and provide reliable support functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 wave-like spring body ensures reliable functioning of the freewheel by providing secure support and even force distribution, simplifying the connection to the rings and reducing manufacturing complexity, while maintaining a compact axial length.

Implementation Method 1

The clamping element is biased into the clamping position by means of a spring element... the elongated spring body having a wave-like course in the radial direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2840274B1Free-wheeling and free-wheeling assembly with a free-wheeling mechanism of this type
Publication Date: 2018.12.19 BORGWARNER INC
  • EP2840274B1 patent drawingFigure 1~2
  • EP2840274B1 patent drawingFigure 3~4
  • EP2840274B1 patent drawingFigure 5~6

AI summary

The present invention relates to a freewheel (4) comprising an inner ring (38), an outer ring (40), and at least one clamping element (48) between the inner ring (38) and the outer ring (40). The clamping element (48) is movable from a clamping position, in which it prevents rotation of the outer ring (40) relative to the inner ring (38) in a first circumferential direction (24), to a release position, in which the outer ring (40) is rotatable in a second circumferential direction (26) relative to the inner ring (38). The clamping element (48) is biased into the clamping position by means of a spring element (64). The spring element (64) has an elongated spring body (66) that extends in a radial plane and has a wave-like profile in the radial direction (20, 22). The present invention further relates to a freewheel arrangement (2) with such a freewheel (4).