Rotation Transmission Device Spring Holder Fixation

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Solution Overview

Problem

The existing rotation transmission devices face issues with high machining costs and unstable snap ring attachment due to the need for flat surface portions on the input shaft for rotational fixing of the spring holder, which can cause rollers to axially move and affect the two-way clutch's functionality.

Innovation Solution

The rotation transmission device incorporates a spring holder with engagement surfaces on its spring holding pieces that engage with the cam surfaces of the inner ring for rotational fixation, eliminating the need for flat surface portions on the input shaft and allowing for a stable snap ring attachment through an annular snap ring groove, reducing machining costs and preventing roller axial movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flat surface portions are formed on the input shaft for rotational fixing of the spring holder, then the spring holder can be rotationally fixed, but machining costs increase

Engineering Contradiction:
Improverotational fixation of spring holderVSAvoidmachining cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The spring holder is divided into multiple spring holding pieces (first, second, third, and fourth spring holding pieces) that are arranged circumferentially. Each spring holding piece has an engagement surface that engages with the corresponding cam surface on the inner ring. This segmentation allows the rotational fixation function to be distributed across multiple contact points rather than requiring a large flat surface on the input shaft, thereby reducing machining costs while maintaining reliable rotational fixation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If flat surface portions are formed on the input shaft, then the spring holder can be rotationally fixed, but snap ring attachment becomes unstable

Engineering Contradiction:
Improverotational fixation of spring holderVSAvoidsnap ring attachment stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The spring holder is segmented into multiple spring holding pieces with engagement surfaces that contact the cam surfaces of the inner ring. This segmentation creates a distributed contact system that provides stable rotational fixation without requiring continuous flat surfaces on the input shaft. The snap ring groove can be formed as a continuous annular groove without being interrupted by flat surface portions, allowing the snap ring to be stably attached and preventing it from detaching during operation.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the control retainer axially moves to disengage rollers, then the two-way clutch can be disengaged, but axial force causes rollers to move axially on cam surfaces

Engineering Contradiction:
Improvedisengagement of two-way clutchVSAvoidroller position stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The spring holder acts as an intermediary component between the rollers and the axial force generated during disengagement. The spring holding pieces with engagement surfaces contact the cam surfaces of the inner ring, providing a controlled interface that guides the rollers' movement. This intermediary structure allows the control retainer to axially move for disengagement while preventing the rollers from moving axially on the cam surfaces, as the engagement surfaces provide lateral support and constraint.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration reduces machining costs by eliminating the need for flat surface machining on the input shaft and stabilizes the snap ring attachment, ensuring proper functionality of the two-way clutch and efficient torque transmission.

Implementation Method 1

elastic members received between the respective opposed pairs of rollers, and each opposed pair of rollers are biased away from each other by the elastic member

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

an electromagnetic clutch having an electromagnetic coil, and provided on the input shaft. When the electromagnetic coil of the electromagnetic clutch is energized and thus the control retainer axially moves

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentEP3104033B1Rotation transmission device
Publication Date: 2020.04.08 NTN CORP
  • EP3104033B1 patent drawingFigure 1
  • EP3104033B1 patent drawingFigure 2~3
  • EP3104033B1 patent drawingFigure 4

AI summary

A rotation transmission device is provided in which an electromagnetic clutch selectively engages and disengages a two-way clutch configured to selectively perform and stop the transmission of torque between an input shaft and an output shaft. A spring holder (50) fitted on the input shaft (1) prevents rollers (15) from axially moving. Spring holding pieces (52) mounted to the spring holder (50) are formed with respective engagement surface (53) engaging with cam surfaces (14) of the outer periphery of an inner ring such that the spring holder (50) is rotationally fixed. Since it is not necessary to machine the input shaft (1) just for the purpose of rotationally fixing the spring holder (50), it is possible to reduce costs.