Self-Aligning Belt Drive With Radial Teeth And Flange

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Solution Overview

Problem

Conventional chain drive systems in cycles face issues like lubrication needs, wear, debris accumulation, and misalignment, while belt drive systems require precise alignment and are prone to debris interference, leading to inefficiencies and increased costs.

Innovation Solution

A pulley and drive belt system with circumferential teeth, alignment flanges, and grooves that allow the belt to ride on teeth while maintaining alignment without side flanges, featuring a configuration where the alignment flange extends radially no further than the teeth, and an alignment groove width ratio matching the belt width, facilitating self-alignment and debris evacuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If side flanges are added to prevent belt wandering, then belt alignment stability is improved, but pulley weight and manufacturing complexity increase

Engineering Contradiction:
Improvebelt alignment stabilityVSAvoidpulley manufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pulley is segmented into functional zones: the outer rim with circumferential teeth for power transmission, and the inner alignment flange for belt positioning. This segmentation allows each zone to perform its specific function without requiring a complete flange structure, reducing complexity while maintaining alignment stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The alignment function is extracted from the traditional side flange structure and implemented through a dedicated alignment flange that extends only partially radially. This extracted alignment feature works in conjunction with the alignment groove on the belt to provide stability without the full complexity of conventional side flanges.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If side flanges are added to prevent belt wandering, then belt alignment stability is improved, but pulley weight increases

Engineering Contradiction:
Improvebelt alignment stabilityVSAvoidpulley weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The alignment function is extracted and implemented through a minimal radial extension (alignment flange) rather than full side flanges. This extracted feature provides necessary belt positioning while minimizing material usage and weight compared to conventional side flange designs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The alignment system is self-aligning through the interaction between the alignment flange and alignment groove, eliminating the need for heavy-duty side flanges. The belt's own alignment groove serves as part of the alignment mechanism, reducing the burden on the pulley structure and thereby reducing weight.

Inventive Principle:
Principle #25Self-service

3Productivity

If circumferential teeth extend beyond the alignment flange radially, then power transmission efficiency is improved, but belt alignment stability deteriorates

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidbelt alignment stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The pulley structure is segmented into distinct radial zones: the alignment flange in the inner radial region for positioning, and the circumferential teeth in the outer radial region for power transmission. This segmentation allows both functions to operate optimally without interfering with each other, maintaining both alignment stability and power transmission efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The alignment groove on the belt acts as an intermediary element that mediates between the alignment flange and the circumferential teeth. It receives the alignment flange to establish positioning while allowing the teeth to extend beyond for effective power transmission, thus reconciling the conflicting requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If the alignment flange extends further radially than the teeth, then belt alignment is improved, but power transmission capability deteriorates

Engineering Contradiction:
Improvebelt alignmentVSAvoidpower transmission capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The pulley is segmented into functional radial zones with the alignment flange occupying the inner region and circumferential teeth occupying the outer region. This segmentation ensures that the alignment flange provides sufficient radial extension for reliable belt positioning while the teeth extend beyond to provide adequate power transmission surface area.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2289792B1Belt drive system
Publication Date: 2015.07.01 THE GATES CORP
  • EP2289792B1 patent drawingFigure 1
  • EP2289792B1 patent drawingFigure 2
  • EP2289792B1 patent drawingFigure 3

AI summary

A self aligning belt drive system comprises a belt drive having a plurality of longitudinally spaced inner lobes each having an alignment groove. The system further comprises at least one pulley comprising a frame configured to rotate about a rotation axis and having a circular outer rim. A plurality of circumferential teeth extend radially and axially of the rim with each tooth being configured to be received between adjacent inner lugs of the drive belt. An alignment flange extends radially between circumferential teeth. The alignment flange is configured to be received in the alignment groove and the alignment flange extends no further radially from the rotational axis than the circumferential teeth. The circumferential teeth, the alignment flange and the alignment groove are configured so that with the alignment flange received in the alignment groove, the drive belt rides on the circumferential teeth.