Pulley Structure for Heat-Driven Grease Diffusion and Rust Prevention

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Solution Overview

Problem

The existing pulley structure design faces challenges in effectively diffusing grease containing a rust inhibitor across the entire spring accommodation space due to a small heat-transfer area, leading to reduced viscosity and incomplete coverage, which can result in reduced clutch mechanism functionality and shortened lifespan.

Innovation Solution

Applying the grease to the facing surface of the inner rotating body, which increases the contact area and facilitates heat transfer, allowing the grease to spread radially outward due to centrifugal force, ensuring thorough diffusion across the spring accommodation space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If grease is simply put into the spring accommodation space in a lump state, then the amount of rust inhibitor used is minimized and labor is reduced, but the heat-transfer area is small causing insufficient heat transfer to the grease

Engineering Contradiction:
Improveease of grease applicationVSAvoidgrease temperature
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The grease is preliminarily applied to the facing surface of the inner rotating body before assembly, ensuring optimal heat transfer contact area is established in advance. This preliminary positioning allows the grease to receive heat efficiently from the rotating body during operation, resolving the contradiction between ease of application and heat transfer effectiveness.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If grease is simply put into the spring accommodation space in a lump state, then labor is reduced, but the viscosity of the grease is less likely to decrease due to insufficient heat transfer

Engineering Contradiction:
Improveassembly efficiencyVSAvoidgrease viscosity
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The grease is preliminarily applied to the facing surface of the inner rotating body in a controlled manner, ensuring optimal contact area is established before assembly. This preliminary positioning ensures that during operation, the grease receives sufficient heat to reduce viscosity and diffuse properly, while maintaining high assembly efficiency.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If grease is applied to the facing surface of the inner rotating body, then heat transfer area is increased facilitating grease diffusion, but the complexity of the manufacturing process increases

Engineering Contradiction:
Improvegrease diffusion effectivenessVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inner rotating body serves dual purposes: it is both a structural component and a grease application surface. By utilizing the existing facing surface of the inner rotating body for grease application, the system leverages its own structure to achieve effective grease distribution without requiring additional complex manufacturing equipment or processes.

Inventive Principle:
Principle #25Self-service

4Reliability

If grease is applied to the facing surface of the inner rotating body, then the rust inhibitor can be diffused across the entire region, but the amount of grease required increases

Engineering Contradiction:
Improverust prevention effectivenessVSAvoidgrease consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The grease is applied specifically to the facing surface of the inner rotating body, which is the local area that requires rust protection and heat transfer. This localized application ensures that grease is concentrated where it is most needed, achieving effective rust prevention and diffusion without unnecessary grease consumption in other areas.

Inventive Principle:
Principle #3Local quality

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 approach ensures efficient diffusion of the rust inhibitor across the entire region, maintaining the clutch mechanism's functionality and extending the pulley structure's lifespan by preventing rust formation and maintaining bearing performance.

Implementation Method 1

heat of the inner rotating body is likely to be transferred to the grease, the temperature of the grease is likely to be raised

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the centrifugal force due to the rotation of the inner rotating body acts on the grease, and thus the grease is also likely to be diffused radially outward

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3604860B1Pulley structure and method for manufacturing pulley structure
Publication Date: 2024.09.04 MITSUBOSHI BELTING LTD
  • EP3604860B1 patent drawingFigure 1(a)~1(b)
  • EP3604860B1 patent drawingFigure 2
  • EP3604860B1 patent drawingFigure 3~4

AI summary

The present invention provides a pulley structure (10) provided with: a tubular outer rotating body (2) having a belt (B) looped thereon; an inner rotating body (3) which is disposed radially inside the outer rotating body (2) and which is rotatable relative to the outer rotating body (2); and a torsional coil spring (4) which is arranged in a spring accommodating space (8) formed between the outer rotating body (2) and the inner rotating body (3). At least in a state in which the pulley structure (10) has not been operated even once, a grease (200) containing an antirust agent is applied to an opposing surface (34) of the inner rotating body 3 opposing an inner peripheral surface (42) of the torsional coil spring (4).