One-Way Clutch Retainer Layout to Prevent Cam Jamming

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Solution Overview

Problem

Existing one-way clutches with resin retainers face issues of cam member jamming and instability, leading to inoperability, and there is a need for weight reduction in mechanical components.

Innovation Solution

A one-way clutch design featuring a resin retainer with alternating diagonal bearing and holding portions for cam members, supported by a spring member, ensuring stable operation and weight reduction by eliminating separate bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a resin retainer is used instead of a metal retainer ring, then weight reduction is achieved, but cam members may bite into or jam the cam receiving portions, making the one-way clutch inoperable

Engineering Contradiction:
Improveweight of retainerVSAvoidoperational stability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The retainer is divided into multiple holding portions (first, second, third, fourth holding portions) that are arranged alternately with bearing portions around the circumference. This segmentation distributes the cam members across multiple discrete locations, preventing concentrated stress that would cause biting or jamming while maintaining the resin material's weight advantage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retainer combines multiple functions into a single component: it provides bearing surfaces through the bearing portions (supporting the outer race) and holding functions through the holding portions (securing cam members). This merging eliminates the need for separate bearing components while maintaining operational stability with the resin material.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If cam members are held in a single continuous receiving portion, then the structure is simple, but stable operation of inner and outer races cannot be attained, leading to cam member jamming

Engineering Contradiction:
Improvestructure of retainerVSAvoidstable operation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The continuous receiving portion is segmented into multiple discrete holding portions (first, second, third, fourth holding portions) that are distributed around the circumference. Each holding portion securely positions individual cam members, preventing them from rotating freely and causing jamming, while the overall structure remains relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The holding portions are arranged in an alternating pattern with bearing portions at specific angular positions around the retainer circumference. This asymmetric distribution optimizes the positioning of cam members relative to bearing surfaces, ensuring stable operation while maintaining structural simplicity.

Inventive Principle:
Principle #4Asymmetry

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 design achieves stable torque transmission and weight reduction by preventing cam member jamming and reducing the number of parts, while maintaining operational stability.

Implementation Method 1

a spring member biassing the plurality of said cam members to no torque transmitting positions

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

the retainer member is provided with a plurality of bearing portions supporting an inner circumferential surface of said outer race

Methodology Applied
Scientific EffectBall bearing: Ball Bearing

Implementation Method 3

a plurality of cam members interposed between said inner race and said outer race to serve torque transmission between said inner race and said outer race

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4339476B1One-way clutch
Publication Date: 2025.04.02 NSK WARNER
  • EP4339476B1 patent drawingFigure 1
  • EP4339476B1 patent drawingFigure 2
  • EP4339476B1 patent drawingFigure 3

AI summary

A one-way clutch having an inner race (3), an outer race (5) arranged on a center axis (C) of the inner race coaxially therewith, a plurality of cam members (7) interposed between the inner race and the outer race to serve torque transmission between the inner race and the outer race, a retainer member (9) for holding the plurality of the cam members and a spring member (15) biassing the plurality of the cam members to no torque transmitting positions. The retainer member 9 is provided with a plurality of bearing portions 31 supporting an inner circumferential surface of the outer race and the same number of holding portions 23 as the number of the bearing portions, the holding portions each holding two or more predetermined number of the cam members with predetermined interval along the circumferential direction, the plurality of the bearing portions (31) is respectively arranged, with respect to the center axis (C), at diagonal positions along the circumferential direction equiangularly, the plurality of said holding portions (23)is respectively arranged, with respect to said center axis (C), at diagonal positions along the circumferential direction equiangularly; and the plurality of the bearing portions (31) and the plurality of the holding portions (23) are arranged alternately along the circumferential direction.