Gear Transmission Retainer Friction Reduction

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Solution Overview

Problem

Conventional gear transmissions with cylindrical roller bearings experience increased friction and wear due to the retainer making direct contact with both the case and the carrier, leading to reduced durability and accelerated deterioration.

Innovation Solution

The introduction of a ring-shaped retainer that contacts both the case and the carrier via separate members, reducing friction and allowing the retainer to rotate at a speed closer to half the carrier's rotation speed, while maintaining spacing between rollers and preventing direct contact, thus minimizing sliding and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the retainer makes direct contact with the case to regulate axial movement of rollers, then the rollers are held in position, but friction increases and rotation speed decreases

Engineering Contradiction:
Improveaxial position stability of rollersVSAvoidrotation speed of retainer
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent introduces a first member (attached to case) and a second member (attached to carrier) as intermediary elements between the retainer and the case/carrier. The retainer contacts these members instead of directly contacting the case, which reduces friction while still maintaining axial position stability of the rollers.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the retainer makes direct contact with the case, then the structure is simple, but wear and deterioration accelerate

Engineering Contradiction:
Improvebearing structure complexityVSAvoiddurability of cylindrical roller bearing
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The first and second members act as intermediary components that reduce direct contact between the retainer and the case/carrier. This reduces friction and wear on the rollers, thereby improving reliability and durability without significantly increasing structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the retainer rotates slower due to friction with the case, then axial movement is controlled, but rolling friction increases and durability decreases

Engineering Contradiction:
Improveaxial movement control of rollersVSAvoidrolling friction loss
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

By introducing the first and second members as intermediaries, the retainer experiences reduced friction during rotation. The first member (attached to case) and second member (attached to carrier) allow the retainer to rotate more freely while still maintaining axial position control, thereby reducing rolling friction loss and energy waste.

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 frictional losses, suppresses sliding and wear of the rollers, and enhances the durability of the gear transmission by maintaining a faster rotation speed of the retainer relative to the case and reducing rotational torque requirements.

Implementation Method 1

the rollers roll along an inner peripheral surface of the case, and also roll along an outer peripheral surface of the carrier

Methodology Applied
Scientific EffectRolling: Roller

Implementation Method 2

When the retainer is brought into contact with the case, friction occurs between the retainer and the case. As a result, a rotation speed of the retainer relative to the case becomes slower

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2980453B1Gear transmission
Publication Date: 2018.10.10 NABTESCO CORP
  • EP2980453B1 patent drawingFigure 1
  • EP2980453B1 patent drawingFigure 2
  • EP2980453B1 patent drawingFigure 3

AI summary

A carrier is supported by a case via a bearing. The bearing comprises an inner race, an outer race, a plurality of rollers, and a retainer. The inner race has a tapered outer peripheral surface, and is fixed to a carrier. The outer race has a tapered inner peripheral surface facing the outer peripheral surface of the inner race, and is fixed to the case. The plurality of rollers is disposed between the inner race and the outer race. An end part of the retainer having a larger diameter makes contact with the case via a first member. The larger diameter end part of the retainer makes contact with the case via a second member. By the retainer making contact with the case and the carrier via the first member and the second member, the retainer can reduce friction compared to when making direct contact with the case and the carrier.